Would this be considered an abusive relationship? It's a little long but I don't know what to do anymore?

My boyfriend and I have been together a little over two years. In the beginning I was extremely happy with things. I loved the fact that he showered me with attention and cared about everything that was going on in my life, which was unlike any guy I have ever been with before. But there weren't and wasn't always the good times. He would party without me and have random girls at him and his friends house. He promised nothing went on, but the doubt consumed me. I got over that for a while but it seems like for the past 6 months or so things have gone downhill. I am moving for school and he has been freaked out by it. He keeps saying if I ever leave him or cheat on him that he'll kill himself. When he says this he claims he's "joking" but it tears me up inside. He always has to dominate the conversation if we're with anyone. He constantly grabs on me in, what I feel, are inappropriate ways in public and it's embarrassing. When I get mad about it he says that he isn't doing anything wrong and that I used to like it when he "showed his affection." He always questions me when I hang out with my friends. If we go somewhere where there are a bunch of guys, like a bar for example, he will literally hang all over me and grab my hand and not speak the whole time because he doesn't like being around guys that might look at me. I also caught him in an obvious lie (the history on his computer) and he denied it and told me that basically I was crazy and that I never believed him but then half an hour later he admitted he lied. We work at the same place (which was how we met) and caught him flirting with a bunch of girls. When I confronted him about it he screamed in my face and made me feel like a dog. I'm just lost. I don't want to hurt him but I can't take this clinginess anymore. I used to be such a strong, independent girl before him but lately it seems like I'm slipping into the background. I've wanted to break up for a while but I'm afraid if I do he will hurt or kill himself and I can't have that on my conscience because I do care about him and his family. Please help, any advice at all please.