heart broken

He made a status years ago before we even started dating about his ex. But he just liked it three days ago. We had the problem first seeing each other that he'd try to get with her and stuff. But she'd turn him down and he can't even add her as a friend on Facebook cause she blocked it. But we've been seeing each other for three years. And I moved in last year. He was never this serious with this girl. They always cheated on each other, and whatever. I've been told by friends I'm pretty much his first real love and girlfriend. Now I think he really loved her and still does. I have a first love that wasn't him, but I'm more than over him. I literally have nothing to do with first love, I don't have him on any social media or anything. I'm very upset because for a long time now he never wants to have sex with me. And he's just not an affection person anyways so I feeel I don't get any attention from him. But I don't try to find it through someone else. I've became everything he wanted in a woman and it's like it's still not enough. I don't know what to do. We live together, have a dog together. And besides this which is a big issue our relationship has been just fine. I still don't think he'd ever cheat on me, but now this just made me think differently and I don't know what to do. I'm literally shaking ready to ball my eyes out.