Two months ago I started getting text alerts of cell phone carrier that I was going over my voice limit, I figured it was me going over, but it wasn't, I confronted my wife and she said it could have been any number of people. I told her the phone number , she scrolled through her contacts and said oh it was a guy from work. Now I normally would not think twice, but the conversation went on for an hour or more, so I asked, what could you possibly talk about for an hour. She said he had some issues with his girl friend and she was giving advice to him. Knowing the type of person my wife was or thought she was I asked how did you make out, she started telling me about him, who is younger, She said OK, I told her our cell plan is limited, so I raised the limit. She stopped talking over the phone, but now they are text messaging like crazy, when they wake up, during work , after work and before they go to bed. How do I know this you ask, well she is not telling me this, but my text alert notified me of coming close to limit. I also noticed the texts coming in on Apple IMessage , again I am not looking for this stuff or checking up on her. It's getting thrown in my face. We have two 4 year olds , I'm 43 and I really don't want to start all over. I feel like this coworker is getting in the middle and waiting for chance to take her away. It gets stressful with the kids, so we argue sometimes. I always told her WE have to talk about it and work it out. I did not confront her about the text messaging yet, don't want to push her away. I ,in a round about way , made a statement, if she would ever tell me if something was going on with her or if she thought that texting people of opposite sex was OK at inappropriate hours. She did not really have an answer, as if it was no concern. She said she text people from work before and I was never upset. I feel like I'm doing my part, working paying bills, taking care of the kids and always try to get alone time to talk or make out, while she's taking zumba classes and getting hot and heavy with coworkers. My gut instinct is telling me something is going on. I feel like I'm getting treated like a fool. I tried to talk to her and see if something was the matter, if she was happy or if there was something I did, What should I do?

Tell her that it hurts that she spends more time talking/texting with him than she does with you. Find a time when it's happening, and don't be confrontational, just hurt, which you have a right to be, even if it's just her helpful and perhaps even motherly nature. (We aren't there to get the nuances of his age and situation, of course.)
A sneaky thing to do would be to enlist a woman you know to start calling you a lot. But that is risky, and I wouldn't do it unless it's someone your wife KNOWS is not a threat. Just to give her a sense of what it feels like.
There seems to be a lot of this going on and getting worse and worse as people become even more addicted to their phones.
You could also text her yourself, and say 'Hey I'm having this problem and sure could use some advice. My wife spends all her time texting advice to someone else.'

Thanks for comment joypulv. I talked to my wife after posting my question. I was up all night, couldn't get sleep, so that's when I posted my question. When I spoke to my wife about what was going on, she was not defensive, but was not sure why I was upset. The day prior I asked her a couple times, " Are you happy, is there anything wrong or is there something wrong with our marriage" She had a confused look, and said no, everything is OK. So , I dropped it. Later on I tried a different approach , I said my friend is having a problem with his marriage, that the wife is texting a male coworker at inappropriate times, and about things that she should speak to the husband about, and then I said "You would let me know if something was happening like that with you , right" Again , she acted no different, and no signs of defense, then she said well you know I text people at work, I said yes , in the past when things were inappropriate , you would let me know. Again ,my wife and I have been through a lot and a I trust her, but I don't trust people who she works with. Some males tell girls what they want to hear and before you it, my wife would be texting to him about things that she should not be. I feel very upset what I'm about to say, but I checked her phones texts, but she had deleted them. Now, I am thoroughly frustrated. So, I could not go to sleep. I stood up all night and went through what I was going to say. When she came down in the morning, she knew something was bothering me. When we were going out , she always told don't lie to me, now she is breaking that rule that she made. I confronted her, and said your hiding something, I told her about I think your text this male coworker is inappropriate and told her how would you react if I was doing the same thing with a girl from work. She understood and she did not want to hurt me. She said she would stop texting him. I felt better that I got it off my chest and told her my feelings, but do I bring it up again, and see what happened or just leave it. I really feel like seeking help with a counselor to see how to rebuild trust, but I don't want to push her away.

I see no reason why you shouldn't bring it up again in a day or two. Tell her that it still feels unresolved, especially when she deleted her texts. (Of course maybe you shouldn't have been snooping?) Tell her that you know people at work get involved in ways that might seem harmless but how are you to know, and what do you do about the fact that it takes away so much time from you?
In some ways it's actually healthy to allow this, so that your marriage isn't confining and stale. I'm sure you get a little jolt from a nice remark from a pretty woman, and it adds to your happiness at home, just to know someone finds you interesting and attractive.
But again - talking it out more than once is OK. Nagging isn't. It sounds like you know where the line is.

I understand your position, I too would be suspicious of my girlfriend if I found out she was texting a random guy incessantly.

Fear not, it is possible that your wife's intentions are innocent and that she actually thinks she's helping him. However, this is guy who's is or about to be on the rebound, so he's likely interpreting this incessant texting much differently.

Don't be around the bush. If you're going to have a talk, have a talk. Be stern with her and tell her that what she's doing is not okay with you.

I am 70 yrs old, retired Mining Engineer. I was divorced in 1975, leaving 2 children with my wife. I remarried in 1977, and was married for 30 years, before she died from smoking cigaretts.
Divorce is not fun, to say the least. Please try talking with her; and please don't play games with her. She is already doing that with this other man. Just simply ask if this marriage is over, and try to get the truth from her. All excuses in the world doesn't make it right for a married woman to be in constant communication with another man. There is no excuse.
You are her husband, and supposedly the only man in her life. I do with you the very best, and hope it eventually works out.

Talk about with her, no games. Try to get answers without her excuses.

I think you should trust your gut. She owes you more than the evasive, dishonest behavior she's exhibiting so far. For a grown woman with children to be texting a man from work after hours is really weird - or at all for that matter. I've never had reason to contact my colleagues after hours except if there was a snow emergency or something that could not wait until I saw them in the office. This is not a coworker relationship - it has become a personal relationship.

So, if your wife's story is that it's perfectly fine for her to have a personal relationship with another man, which does not include you and which she conducts secretly, you have every reason to be suspicious. Divorce may not need to be the first step but you might need to let her know that if the relationship continues you will consider it an act of infidelity and will respond accordingly. I would not accept her saying she didn't mean to hurt you. She meant to deceive you and have a shady side relationship with another man, which she knew would hurt you if you found out about it. Even after you called her out on the phone bill problems the first time, she continued so she was flagrant about it. As such, she absolutely didn't make your feelings a part of her decision making at all. Disregarding your feelings is hurtful, and she did that deliberately. She needs to end this relationship and probably find another job away from this guy for the benefit of your marriage and family. It is entirely reasonable of you to ask her to do just that.