Sleeping with my ex?

Okay so back story... my ex is the first guy I every kissed when I was 21 he also broke my heart after 5 months of dating almost 2 years ago. We weren't in eachothers life for a year and then due to mutual friends we started talking again occasionally. During this time I learned I love giving blow jobs and overall am a very horny and sexual person. We ended up meeting up and hard core making out and pleasing each other back in may the come June my life flipped upside down with my mom dying and I ended up sleeping with him. He used me for sex and I used him to turn my emotions off but I also wanted sex. That was my first and only time.He also ended up bragging to people about the fact that we slept together which caused a bunch of issues because no one knew we were in contact with each other. In the last 2 months he's hit me up a couple of times not just in the middle of the night but in the middle of the day asking for sex knowing exactly what gets me horny but I still have said no because the girl I was when we slept together was in a very dark place and I'm trying my best to make myself better but I'm also horny as hell and I want to fuck and he knows exactly what I like. I don't know what to do?