Growing jealousy - toxic

Hi guys, first post here, but after reading a few very interesting comments I thought I'd give it a shot at being helped...I've been in a relationship with a new guy for about 2 months now. I've been in long term relationships for about all my life, and had just a few moments where I really wanted fun... When this happens, I usually only do soft (like oral) and get it over with as soon as possible... I'm kind of a hopeless romantic... And for me sex and feelings are connected and rarely dissociable. I like to have a life with boxes... And clear, defined relationships with the people I frequent.Now, the guy I'm with is quite different. We have very different values, and different perception of relationships. For example, I'd never go open relationship, but he said he would.That's for the background. He's 19 and I'm 28. The question is not necessarily about the age, but it is influenced by it...Anyhow. Recently I've been having a super toxic behavior. I used to be very respectful of my ex bfs privacy... For example if one day they wanted to go out in a gay club and I didn't, he could go alone. I wouldn't never check their social media...What I struggle with here is that my bf is just constantly checking out hot guys on social (Instagram), reminding me he's fucked with this one or had sex with this one, know this one from YouTube or Instagram, reminding be that he wouldn't mind fucking this other guy (but ofc he doesn't since we're together), or that he needs to be hot in his pics (to get more likes and shit), the first thing he does everyday is not speak to me when he wakes up, it is check out his freaking followers... Like literally opening his Instagram, look at the listing Oh who commented and liked, and go through every single one to like their pics if they're hot... Now it's gotten to a point I'm checking who's commenting on his pics that he's hot (and who he likes)... This is just horrible. My heart races super fast, it's silly, I feel horrible and unwanted. He's got me so destabilized with all this, rubbing in my face all these other guys... It's so draining. It's a bit too late now, because of his behavior I'm so insecure... I used to be so confident, never posting any pics of me, never looking for social media validation.I'm getting paranoid too, thinking things like: he must receive messages too, here, maybe he flirts with others he find attractive, let me check who keeps commenting... He has his snapchat there maybe he receives dick pics often and send out some... Maybe bla bla blaThat really hurts me... I feel so shit and don't know what to do... Like yesterday he was speaking about how he still has all those "friends" he had sex with and like they often speak etc... And for him when he has sex its more than just a shag, he likes to know the person more and bond with them... So I feel like he has all this really weird patchy relationships, where it's not just sex but also weird feelings and affection, and he's still in touch with all... These regulars.... I don't know. It's so weird for me. I was so grossed out. I feel so threatened. I barely slept and felt like crying... There's nothing really just this looming impression and constant threats... He doesn't mind telling me, when I ask who's that guy, "oh we fucked once or twice that's all". And the worse, all these guys live near us (he's my neighbor) like the guy living the flat just under mine has fucked him... I see him in the elevator, I know, he knows... It's a cruel reminder.I know there is a gap of generation ... I asked once if he could check these guys on instagram when I'm not here. Just don't do it next to me, I'm okay you live your life... But yeah. Just a bit of respect? He did for a few days but it's back to doing it next to me. Before sleep, when waking up, when I would like us to Watch a movie... If I buy him flowers first thing he does is post it on instagram stories, posts about him waking up, etc... This is so silly. I just don't get it.And now, it's really eating my from the inside, I'm getting paranoid, as I said... And the slightest thing makes me wonder plenty...I just don't know what to do. I've started a new Instagram account where I post pics of me this week, just to show him how meaningless all of this is, almost to "teach him" some humility... Show him if I do that I get plenty of messages of people asking for dicks and cuddles, or meet etc... And how much that hurts when you're the other side. I plan to check out hot guys in front of him and leave comments...I don't know how much I've fallen to be so stupid and play that game...Anyone lived this...?Sorry for the wall of text.