<human>: So my ex broke up with me three months ago because he felt like he couldn't be faithful to me. After waiting around for him to realize that he made a mistake for two months (all through which he was having sex and dating girls) I found out he was dating a girl. So I started seeing someone and we slept together. Now my ex wants me back and I'm actually considering dating him again. I'm not here for you to tell me that it's a mistake because there's a lot more to our relationship than a text post but he won't be okay with me having slept with someone else so is it okay if I don't tell him? I mean after all we weren't together...

Can you provide a brief overview of the text?
<bot>: do I have to tell my ex that I've had sex with someone else while we were broken up if we get back together?