Can’t get over him

Me and my bd has never been in an actual relationship but if you was ever around us you’ll think we are, since having a child a lot has changed don’t get me wrong before getting pregnant we had a lot to work on but since it’s been Broken trust, lies nd more .. and most of it has been on his part. Every time we move forward it’s 10 steps back. Anyways we been having sex again, and he normally pick and chooses when we do. (We could have sex everyday for a week then next thing you know he doesn’t want to be touched or fuck, and he’ll start ghosting.) friends think it’s when he has another female involved he treats me like that but he swear up and down that’s not the case. He claims he doesn’t want a relationship, he doesn’t want us to be a family just coparenting but then he acts possessive and jealous, he checks my phone and it’s constantly questions about my plans or whereabouts. I know this isn’t healthy but knowing someone for 4 years it’s hard to let go. I genuinely love him. Lately I’ve been trying to set boundaries. But he’s so tempting any tips on how to keep it up?

Edits: thanks for the comments I’ve been rereading and letting everything sink in. I’m young (18) and still learning. Everything you guys said is very much true. I need to acknowledge it more. Him and I basically grew up together same elementary, middle and high school we didn’t really acknowledge each other till high school that’s when it became sexual. I obviously need to let go and ik I will.