Relationship/Break-up question

Hey! Need some advice because this is eating me up and need to know what other people would do! 💕

So me and my ex broke up In January (he broke up with me). He told me that his heart wasn’t in the relationship anymore and that was it, him and his family blocked me on everything so i had no way of contacting him so as far as i was aware he wasn’t coming back!

During the relationship he emotionally cheated on me and was paying for girls onlyfans and had a whole hidden folder full of *** of other girls which i found and i chose to forgive him and we moved on from that!

So after about 3 months after the breakup i met up with a guy who i’ve known for years but also haven’t spoken too in years and we ended up sleeping together, i regretted it because that is not how i wanted to get over my ex and heal and i haven’t been with anyone else since that!

Now a few weeks ago my ex reached out and apologised for everything he put me through and how he dealt with the breakup. We aren’t back together but we have slept together a few times and also message daily and play video games together. I know he speaks to other girls and has been sending them pictures and receiving them and it’s not my place to bring that up because technically we are single and NOT together!

I just wanted to know if i NEED to tell him about the guy i slept with during this breakup or if i don’t owe him anything because i’m single?

💕💕💕