As I've said here in the past, he's making the classic mistake of comparing the beginning of one relationship with the middle of another one. That's a very hard thing to fight, unfortunately, and I have no wise counsel for you, except start doing what you need to to protect your interests.

Eventually, the bottom will probably fall out of this relationship for him, or the thrill will go out of it as the every-day hum-drum sets in, and he begins to realize that the problems in that relationship are remarkly similar to the ones he had with you. Maybe he'll be back then, scratching at your door. It happens often enough to women on here. At that point, it's up to you.

I'm sorry for your pain. Focus on the things you CAN control right now. Take care of yourself. Protect your interests.

remarkly = remarkably

Trust. One of the foundations of any relationship. Can you trust him moving forward if he calls it quits.

In my experience, once a wanderer always a wanderer.

Okay, you are probably not going to like my advice but for what it's worth...
There is really nothing you can do to 'win' him back. The more you try,the harder he will run. Just work on yourself, be independent, not at all clingy. Tell him your feelings in a direct and honest way and leave it at that.

I personally believe that a person can't be seduced by another unless they were already unhappy to begin with. I wouldn't think of this as a tug of war between you and her. He's going to do what he's going to do and really there is not a whole lot you can do about it. You can be kind to him, show him you are not afraid to be alone if it comes to that, tell him you love him and want to work on the marriage with him (as long as he gives up the OW) but that he needs to realize that once he leaves, you may not take him back later if he decides that the OW isn't everything he hoped for. Maybe that will make him think twice. I think that sometimes when people are leaving for another person, they secretly like the fact that their spouse is clinging because they think there is a backup plan if things don't work out with the new person. Even if you think you would take him back, don't let him know that. Make him think there are real consequences to the choices he is making. Good luck.

The previous four posts say it all! Although, I have a new perspective on the "once a wanderer, always a wanderer" issue. I AGREE with that, but there has to be a first time, right? If this is his first time to wander, was there an event in your relationship that made him take the wanderer plunge? Usually, there is more to it than "he does not love me the way he used too." That would be something I might say to spare someone's feelings. If there is something YOU want to change about yourself, work on that. If, indeed, he still loves you, he will notice your effort.

I'd have to disagree with zoom--HE is responsible for "wandering", NOT her. We are not responsible for other peoples actions/behavior, only our own. Many people go through trying times in relationships and DON'T cheat. There may be an EXCUSE why he decided to cheat, but when it comes down to it, it has very little to do with redheaded peach!

I wasn't suggesting she is responsible. It was a rhetorical question about what launches behavior. Sometimes, it's a single event, sometimes it's a build-up. In RedeadedPeach's case, she doesn't know and might like to address parts of the relationship that are lacking. We all have needs. She loves her husband and by her discussion topic, is willing to do "something" to "win him back". Unless you know what the issues truly are, they cannot be addressed. In my relationships, I want to know the strengths and the weaknesses. That's how I improve myself.