wtf do I do(advise)

Okay so long story, but I have to make it shorter. So me and my ex were talking, (I know) I broke up with him 3 years ago, we in highschool and it didnt work. And we were talking and he said he still loved me and i felt the same way. a few months go by and he said he got a girl pregnant. He said"last summer i was at a party and was drugged and got used by a girl" which I know can happen. but fucking weird part was today,(I check his profile and such and saw him tag with him with a girl, holding hands. I was shocked the girl was saying how much she loved him 🤐. I was like wtf.... And we plan on seeing each during summer... So his lying bitch? and the funny thing is that I had a misscarge when we broke up. And he was saying how much he wished it was me and not her. (girl he got pregnant) and they were smiling and holding fucking hands. wtf did I get into tooo!!! ahhh help

update: I texted his "girl/baby mama" and gave her info on what he was doing.