falling out of love?

I no longer feel like I'm Inlove with my partner. I feel like sex is meaningless and majority of the time I make excuses as to why I don't want to do it. When we do have sex it lacks passion and I just sit there because I truly just don't have the want to have intercourse with him. I notice his flaws a lot more and I have realised he isn't that great. He doesn't really show he loves me often, pointing out my flaws, saying negative things etc. and that made me extremely insecure to the point that on New Year's <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> I told him I can't deal with it and that he has a month to change or I'm leaving (our 1 year anniversary is on the 28th). The thing is I know I don't love him but the thought of leaving him saddens me. Everyone tells me I could do so much better as he is a dickhead to me 98% of the time. I don't even want to kiss etc. I just am so used to the attention and all of that, that I don't want to leave because I'm not sure how I'd be without that attention to rely on. Everything he does pisses me right off which never used to happen. Help, what the fuck do I do? What do you suggest? Ever had something similar?