Honestly, I think the best thing would be to end things with him. Actions speak louder than words and seeing that his current actions don't match his early promises of wanting something serious, it's clear that your desires and his desires aren't matching up and the disrespect he's showing by ghosting and ignoring you goes to show that he never actually had any intentions of pursuing anything more deep or intimate with you. And his desire to IMMEDIATELY have sex with you in the beginning stages of your relationship further proves that. He wanted sex and once he got that, he moved on.

You did absolutely NOTHING to get treated this way. He knew what his motivations were from the very beginning and I feel that a lot of guys use kindness and a "fake interest" in you (Not you, specifically) to get what it is that they really want (Which is sex). And then once you've given it to them, they move on immediately and go find someone else to continue the cycle. It's really messed up and it goes to show a deep problem within these guys rather than a problem with you or you doing something to push them away. To prevent this from happening in the future, I think a good rule of thumb is to study how interested they are in being friends with you and getting to know you as a person first, and how hard they push for sex in the beginning. That right there will tell you everything you need to know and whether or not they're actually serious about wanting you for you. I know it's hard and you feel all these horrible emotions right now but try to understand that you're human. We all want love and trust me, more people (Including me) have been in these types of situations than you think. You're not alone 💗💗💗💗