SadMommy;

I had to reply to you. I am a male, been married to the same woman for 34 years. Your situation is pretty common in marriages. As we get older we men tend to lose our focus in life. Some get a divorce and hook up with a young gold digger. Some just want to be alone so they can play the field, so to speak. Then there are those that like to play "flirting games". Some men like having female friends
to talk with other than their wife. This last type walks a fine line and can get into a lot of trouble. I speak from experiance. Wanting to feel desirable from another woman is a great feeling for a man but, he has to know how to control himself. It is nearly impossable to be platonic friends with another woman while married. It leads to disaster. Getting involved with another woman while married will be found out. A wife dosen't have to snoop to know that something is wrong. Men are not as sly as they think they are, it will be found out, they will get caught.
The biggest problem will be the ability to trust again. With you having been burned once before it will likely be impossible to trust again.
You and your husband need to speak frankly to each other.
Ask him if he wants your marriage to continue. If he wants out, then let him go.You can't do anything to stop him. If he says he wants to stay then lay out some ground rules.
No e-mails, no messages without you knowing it. No late at the office without you being able to verify it.
In 34 years I have not always been faithful but, for the last 25 I have been. It was a long hard road back to getting the trust again but, I made a commitment years ago and I intend to keep it.
Good luck to you and I hope it will work out.