Are my friends right?

I had a fwb for a month. He turned it into something romantic and that lasted for a week before he ended up ditching for another girl. He came back and said that he was going to be serious about me now. I was an idiot and took him back bc I believed it. But I still don’t think he’s really serious. I caught him in what I feel is flirting with the other girl (he doesn’t know I know) one time at work and he’s admitted to talking to her but says it’s work related. Then he started to seem distant and only really flirted when he wanted sex so I got distant too. But then he saw one of my work friends and I talking and accused me of being with him on the side. Started saying how he wants more attention and started saying how it bothers him that when I come in, I talk to my friends and not him. How I should be making him feel comfortable and special. When I mentioned that I try to spend time with him and he says no, he says it’s bc we “work different shifts” but he’ll make time for sex? He also used to make plans every day but then stopped. Or I’ve tried to talk to him more and he was dry. Then when another guy came in later that day, he stood nearby and I could tell it was to see if I would talk to him (he’s told me that if I talk to the other guy, he’d be done). He also asked me not to talk to the guy he accused me of dating outside of work.

Since that day (it was all one day), he’s been putting more effort into actually talking. But i know he’s only doing it bc he feels threatened, but when he flirts with someone else it’s okay? My friends say he’s just becoming super controlling and is treating me like property, not someone he actually likes, and that I deserve better.