I need help

I really want our relationship to work out. I’m a teenage girl and I have a long distance bf who’s much more older than me. We’ve been dating for 2 years. Everything was going well for the first year. I was happy and feel safe with him. But then I found out he cheated on me and we got into a triangle relationship for a while. He eventually cut off that girl. But now I don’t feel safe with him. He said he feel bored with me. Every time we call it’s either fighting or stress talk. I try to have a non pressured conversation with him but he keep bringing up sexual topic like doing threesome. I feel uncomfortable. I can’t say it cause he said it’s his honesty. I told him to share everything in his mind with me. Then he said he don’t like how I look anymore. I look better back then. And he’s tired of online relationship.

I’ve tried everything to make him happy. Such as learning about his hobbies, play games with him, fulfil his sexual needs. But how come it’s still not enough for him to appreciate me? Right now I’m just stuck. I very attached to him but I know he’s not good for me. And there’s no way I can change him. Please help