Found out my ex cheated on me after we broke up. Do I have a right to be upset?

[Caliigirl]

I was with my boyfriend for a total of 13 months, and 3 of those months, we were separated. After the 3 months, he messages me telling me he misses me and whatnot and I was missing him like crazy as well. We met up that night and started talking talking again and then before you know it, we were back together. But after we got back together, he started acting his old self (which was the reason why we broke up in the first place). He never made an effort to see me, never texted me, always bailed on our plans, and a lot other things. So I was talking to him about why he was doing all this if he says he missed me and out of nowhere he accuses me of sleeping with another guy while we were separated for those 3 months, which is absolute bull, I wasn’t even talking to anyone. So I ended up breaking up with him for good. And then about a week later, my friend tells me (my friend knows my ex also) they were hanging out and he was snapping someone and it said “baby ♥️♥️♥️♥️“ and she obviously tells me. So he was trying to get me back while also talking to someone else. Should I let this go or let him know that I know? I’m just so upset and hurt that I just want to cuss him out.

Updates:

[21feminist]

Ah... You have the right to be pissed but you can't expect that to make you feel much better can you? Plus it'll give him the feeling that you're still thinking about him. Which may or may not be true. The point is telling him you know bout what he did couldn't actually benefit you in any practical way. You need to focus on yourself and mainly your self improvement. By doing better without him you'll feel much better.

[Nocturnal0808]

You should forget about him and focus on what lies ahead of you, not behind. You'll find someone better.

[miiszmel]

Of course you should be upset.
He wanted you back and then didn't even make an effort to see you and text you.
Obviously he just wanted a side piece. He's a selfish dick.
You deserve better.
there's way better guys out there.
Just try to move on from this.
he's not worth it

[LeftMark9]

Usually when someone is doing the wrong thing they will get defensive and say that you're doing the wrong thing. I've been in your situation and I told him that I knew. There is no reason why he should get away with what he did to you.

[kentlevi]

If you don't break up with him you're an idiot because he'll do it again.

[Guyz0]

If you're already broken up, not much you can do at this point other than accept it

[Anonymous]

He is your ex, so yes it sucks but your no longer together

[duces]

cuss him out fuck him he's being a duche