I probably need to leave (TW)

I’ve been with my partner for 2 years now. I feel unimportant to him. There are days where I feel like he loves me and cares about me. But the bad days out number those. The bad days are when I want to run an errand and he stays home (he has a car) and the minute i get home he leaves and does whatever. He doesn’t include me in anything. All he does is reminisce over his past when he was single and doing everything he wanted. I always use “we” “us” I have always made him feel important. I have 2 kids that aren’t his. And he says he wants to step up and help and be a great step dad, but he never does anything with them. He still makes fun of people our age that have kids because he “doesn’t have any”. I know I need to leave. I know it’s best. But for some reason my heart cannot let go and stop chasing this man. I’ve fought through hell and back to be with him. I feel like I’m the only one that’s ever fought for it. I’m feeling drained. He doesn’t comfort me but i have to comfort him. Tonight is Valentine’s Day. And he didn’t get me anything or say anything to me. Instead I bought HIM dinner, put gas in his car, bought him the things he needed. And he’s at his mommy’s house because “I’m going to see what my mom got me for Valentine’s Day” he knows his mom only belittles me, hates me, and degrades me every time he goes over there. To the point where she will literally throw a fit if I show up with him. So here i am on Valentine’s Day in the bathroom naked with the shower not running and i self harmed tonight after not having done it since I was 16 years old. I just need someone to tell me I’m not crazy. And I’m worth it