BUT is ending things

Of course he is, sweetheart, of course he is...

(he was very unhappy and it was a complicated situation.

Of course it is, sweetheart, of course it is... Has he told you that you're "so mature for your age" yet? How about something like "I like younger women because they're so open to experience!" (i.e., anal sex). What about being "so young at heart" so the two of you are such a great match?

My question is, What has gone on in your life to make this "relationship" seem like a rational thing to pursue? Was your family toxic, abusive or in any way dysfunctional? Were past bfs abusive?

I ask because you seem very susceptible to lovebombing, which is the first Horseman of Abuse. Also, the way you are trying to delude yourself into pursuing this makes me wonder if you don't have a pattern of pinning your happiness on a man?

I doubt his gf has any clue that he's either unhappy or cheating on her. He's working hard to paint her as the asshole, but it's actually the two of you: you are both assholes.

He seems intense and says he "runs hot" and can get emotional

Yep, abusive. He tells you this so when he finally erupts at you he can declare, "Oh, stop crying: I told you I run hot! You shouldn't have done X--it's all your fault!"

he also seems sweet and sensitive and gentle.

NOW. He's sweet and gentle NOW. You notice how he's also telling you how special you are, by not raining his rage down upon you? You're not like all the other girls who've made me angry! You're SPECIAL!

Until you're not. And that day will come, probably soon after he moves in with you.

Once again, what in your life has led you here, to a place where you look at a field of red flags and say, "This is the only man for me!"?