Me and my wife separated 2 1/2 months ago and she never told me why except that she wasn't happy. After a 5 hour conversation with her last week she confesses she has been carrying on a year long affair with a co-worker. She wants to fix things now and we have both enrolled in individual counseling. I asked her to cut off all communications with him and she tells me she has, although he is a co-worker and they will see each other frequently. When she says she cut ties she says she told him everything and told him not to interfere as she wants to fix her marriage and that they are finished. We have been married six years and both have high tempo jobs with long hours. My work requires me to leave for very long periods every 2 to 3 years as well. Her job is local but long hours on the road. I just want to know if its possible to save a marriage if a spouse has been carrying on a year long affair with someone else or is it better to just let it go?

You are asking strangers something that cannot be answered except over time by the two of you. The fact that you hope for an answer suggests that there might be something about you that is a little too concrete. The old saying 'it takes two to tango' applies in all situations, including what drove your wife into another man's arms. It isn't all about some deep problem of hers, but a problem of both of yours, about your ability to express yourselves and your wishes and needs to each other, and to say what is lacking and then work on how to fill the voids.
I wonder if individual therapy is what you each need. There could easily be nothing deep seated in either of you, and it's all about the long work hours and the lack of communication. Couple counseling, which teaches two people how to communicate (and not who is right or wrong), might be more applicable. It's also shorter term.

This is something only the two of you can answer. If you still love her and feel like she is worth working through this for, then definitely go for it! If you feel like this is something you will never be able to get past especially since she works with him, then walk away. If she is doing what you have asked of her, then I feel like she actually regrets what she has done. We are only people, we all make mistakes. It takes an amazing individual to be able to forgive those mistakes.

Of course since you both work long hours, and you can be gone for long periods for your job, you need to find something that will both make you feel secure in your marriage. You need to find a way to make time for each other. This could be something as a date night every now and then. Or simply bring her a flower, something to let her know you still love her and she doesn't need to seek comfort with another because you will be there no matter what.

I would also let her know that if you decide to work through this that she isn't going to get another chance. If she does this to you again, I think the problem is much bigger than a simple mistake. You need to be able to trust your partner always.

I hope everything works out for you.

I don't think you should waste your time. In my opinion if someone cheats for that long they don't really love you. Its all bull to me, I can understand a one time thing but for that long I think you'll be wasting your time when you can find someone else who's worth it. But its really up to you and if you can see a difference in her .

Only you know your wife and your relationship. I believe everything can be fixed if you BOTH really want to. But that is the question whether both of you want to. You will only discover that with time and work. Counselling can be useful, but maybe you should go as a couple. It might help you communicate better.
Of course, leaving her is much simpler and quicker. If you stay and try to work on it, there are no guarantees. You could try your hardest for a number of years and still lose her. If you leave/separate you are guaranteed to lose her but also the trust issues and hard work. So maybe you have to weigh up the 2 options and decide yourself.
Do you really want her that much? Can you imagine life without her? Would you be able to forgive her? Could you ever trust her again?
Big questions...

Why not give it a try. It's good that you have asked for professional help. Wish you both well.

Sounds to me like you both need different jobs if you're going to try to salvage it. She should absolutely not be in proximity to him, job or not. And time away from each other didn't serve you well, it would seem. I wish you the best, as well.