soooo something happened

so long story short, my ex boyfriend broke up with me back in December. we still see each other a lot though because we work together. I know, work relationships (omg!!) but we're friends now so it's cool. and I'm over him, I don't have any feelings for him anymore and I'm 98% positive that he doesn't for me either. but fast forward to last night, we were texting and we were talking about something stupid and I said "I bet I'm better than you" and he goes "are you seriously challenging me right now?" and I said "yes 💁🏻" and he goes "okay, I'm all in, if you win you decide whatever, if I win, you go buy condoms and we have sex again" and I said "okay, deal. let's do this" and I go over there after buying condoms and we didn't even do what we were betting on, we just started making out and then it escalated into is having sex for a while (FYI, period sex is 😍😍😍😍) and then we stopped and just cuddled naked for a while and then we went for round 2 and then after round 2, we were talking and he was like "this has to stay between us, we can't say anything to anyone " and I said "I mean if you really think about it, this shouldn't be a big deal because we're over each other right ?" and he goes "I can't be dating right now" and I responded with "that's not what I'm saying, I'm asking to make sure that we're both over each other right ?" and he goes "yeah sure, I guess" and we just kinda left it at that. I went home and I haven't talked to him today yet.