I have been through years of court conflict, back and forth, child support issues etc. After all these years I've learned alot, especially what not to do. Your children are teens, right? It's really up to them who they want to live with. They shouldn't have to choose based on what has happened in their parents relationship. They are also old enough to see if your soon to be ex is being manipulative. I would just try to be supportive and no matter how much it hurts it's important to let them make up their own minds. They will make the right decision, and if they don't it will be a learning experience for them and will help them to move on. I too devoted my entire married life to my children. My ex was always away or too busy. He also had many affairs and spent our money on other women. This is not something I have told my children as it is not really their business and will only hurt them and make them feel torn. I have three children and since they were 10 I let them decide when they want to see their Dad and I stayed out of it. I know it hurts to see his side of the family cut you out but that is the result of divorce. They can't invite you anymore as you are getting divorced. I remember going through that and having to put up with my kids going to their grandparents on holidays with their Dad and his new girlfriend. It hurt that I was left out but there was nothing I could do about it and it was important for my kids to move on too. I just went out and made some new friends and got on with my new reality. It all takes time though and you will feel better soon. I am great friends with my ex in-laws now. They invite me to dinner on holidays. I also have them at my home. They just invite me and my kids over at different times and my ex and his live-in girlfriend over at other times. It works out well now but it took time to get to this place. It is really important for kids to have two parents. They love their Dad no matter what he did (to you) and they always will. They can't think of him as the bad guy as that causes them great distress and they don't need this on top of everything else. I think they feel torn because they have too much information about your personal issues. They shouldn't have to take sides. It really is not there business that your husband had an affair. Your relationship issues should not be taken on by them and will only cause them turmoil. It's so important to put our kids first when it comes to divorce. Their entire life has been turned upside down and they don't need to take on their parents problems on top of everything. That is not fair to them.
I'm not trying to sound harsh and believe me I know what you are going through and it is unjust and heartbreaking. I moved on by meeting up with other newly divorced Mom's and vented to them instead of my kids. I took my kids to a "caught in the middle" program for kids of divorce and also took my eldest to counselling as he needed it. I wish you well, you will get through this but you have to let go of the anger towards your ex and what he has done to you as it only backfires on you. Forgiveness sets you free. You don't have to forget. As for other men and trusting them this takes time too. I spent at least 5 years disliking men and not trusting any of them. But I have sons, and so do you and they are men, interesting isn't it. You will meet a man that is worthy that you can trust but now is not the time for that. Do whatever you can to move on. This will also benefit your children as they will see you happy again and they won't have to worry about you which will make them feel more content in themselves.
Hope this helps.
Kate