I am sleeping with my ex husband.....

Umm I have been divorced since 2013, it started after he almost died from covid and we have kids together our kids didn’t feel like he was being honest with them sooo they came and asked if I could find out what was going on... So I reached out and to my surprise he started talking to me, he was starting to apologizing for what happened in our marriage etc... It was nice to hear after being accused of why it failed..... So I offered to help get stuff and drop it off to his mom’s home once he got out the hospital and his wife could pick it up and give it to him and come to find out he says in the middle of a conversation “I am separated n am homeless of about 7 months”! then 😳🤭... I felt bad for him see I saw it as to help him it was good our kids see us get along.. Well he was on oxygen once they released him from the hospital but one of the tanks didn’t work so he asked could I pick up the new ones n drop it off so me being nice said ok (this is cool nothing what could happen)? I got there n I promise I had on a Nike sweatsuit nothing sexy or cute... He just grabbed me n pinned me against the wall I told him to let me go n he didn’t (it has been 3 years since I been with anyone my boyfriend was murdered) apart of me still love him we have kids together however I don’t want to be with him but the sex is omggggg..... How do I stop sleeping with a man who is separated? We don’t talk about her? We don’t talk about what we are doing? I think it’s because we are safe n familiar to one another... I never thought I would go from him cheating on me to him cheating with me??? I understand both sides of this n I do want him back I didn’t want to divorce him in the first place but he didn’t want to go to therapy so I filed thinking he would say she is serious n fight for his family well it backfired!!! He knows I love him cuz our kids but he doesn’t know how I feel about him... My apologies for this being allll over the place..... What should I do please try not to be too harsh on me.... Thank u guys for reading n responding in advance....