Welcome. I'm sorry that you had the reason to find us, but I'm so glad that you did! We are here to support you. The weekends can be a bit slow, so please don't think that you're being ignored if not too many people respond immediately. The forum picks up again on Monday big time.
If you have not already done so, please look up to the left side of your screen for a yellow box. Click on The Healing Library. Read it. There is a lot of good information in there for you that has been written by people who have walked in your shoes. Also, any post on this forum with a bulls-eye next to is also has good info for you. Knowledge is power, so please, read.
Cutting to the chase, your BW cheated on you. He committed a sexual act, an act of intimacy, that should have only been performed with you. Further, he made the decision to contact the OW, make an arrangement to get together with her, get naked, and allow and encourage her to get sexually intimate with him. He "says" that he couldn't perform. He probably says that this was the first and only time too. And after all, it's been an Whole Year...
He is an adulterer. This probably wasn't his first time. Why? Well, because he is a liar and liars lie. And it's been a year for him? Well, it's been 5 days for you. And coming off of your previous marriage, it's even more shocking, if that's possible.
We set up terms but he is trying to bargain
Bargain? The fact that you are willing to even tolerate him in the house is a gift to him. He had best shut his mouth, pull his head out of his arse, and start doing anything and everything that YOU need for him to do. HE BOMBED YOUR MARRIAGE! Him thinking that he has the right to bargain about what you need to try to heal is like the Boston Marathon Bomber bargaining about if he should be able to get a weekend pass to go see a movie.
Please come back often and post. We're all here for you. (((hugs)))