I can understand your aprehension about the OM with your kids. The same thoughts have gone through my head. In fact, those thoughts happened so early on in my situation that I called him up so as to find out what kind of guy he is.
I cannot argue against what has occured to your marriage and family. It happened. Sh!t happens. What your XW and OM did is absolutely disgusting, and even though I am not religious, I would still call it a sin. A violation of basic morality and honor.
What if they do get married? And your kids have a step father. They may even call him dad. That is my reality and I am accepting it and am not letting it eat away at me. I just do the best I can when the kids are with me and they know that I am their real dad. I teach them morality through my actions and consistency. I am letting them come to their own conclusions over time as what right and wrong is. I trust that they are smart and perceptive kids.
I know you hold a lot of resentment because he and your exW are both responsible for breaking apart your family. But I think your anger towards this situation is just going to make it harder for you to heal and move forward. Some people (well maybe a lot) just dont have very high morals. But instead of trying to figure out why someone can stoop so low, you need to learn to detach more. Become more of an easy come, easy go, happy go lucky sort of guy.
It is up to you whether you want to continue to fight this in your mind. As long as you do, you jeopradize your long term happiness and become a turn off for future ladies. I believe it is so very much easier to be friends than enemies. It just takes a leap of accepting that things are what they are.
