My wife has a guy friend at work that she has started texting late at night and she started smoking at work and I asked her way she started smoking. She tells me she wanted the break and to have time to talk to him. She is also talking about him a lot. I don't know if it is just me being crazy, or if I should be worried.

Her taking smoke breaks with a guy at work, in itself, is no big deal.

Her texting him late at night, is.

Your wife has no business texting a man, not her husband, from work, late at night.

To answer your question, "is my wife cheating", you don't have enough information, or provided enough information here, for anyone to hazard a guess.

Do you two communicate? You should express your concerns in a nonthreatening nonaccusing way. Is nonaccusing a word? If not it should be.

I agree with Jake2008 - she shouldn't be texting another man late at night.

I'm wondering... are you saying that your wife actually started smoking so that she could take breaks to speak to this man, or is she already a smoker and just started smoking at work too?

I don't know if she is cheating, and she tells you about him, but talking and setting boundaries of good behavior would be the way to go. That late night texting ain't the best thing in my book, but that's to discussed.

I would say something.

Seems like she is in love with him. A Strong love!
Talk to her openly, and ask her if she is in love.

Then go from there. If she says she is, then case closed. If she says she's not, then ask her to explain all those strange behaviours. If she can't, then she is lying, she is in love.