Our whole day was ruined because I said no to having sex

So a little background; the relationship I am in right now, ive been trying to get out of for a while now but haven't had the balls to do it. Im just scared of change. Its toxic, hes controlling, and im just not happy. He used to be a lot more controlling but it seems that every time i try to leave, he turns it down juuuust a tiny notch, enough to make me stay because there's "improvement".

Anyway, because of all this, I am not sexually attracted to him. I've tried to tell him this in the past, but it turned into a whole argument and him saying "did you really mean that 🥺" over and over until i said no.

Yesterday, our son was with my dad for a couple hours. When they left, he asked me if I wanted to have sex. At first I said I was tired, which he replied "thats bullshit. Its 2 in the afternoon" and so I said I just really wasn't in the mood. After some bickering back and forth about it, I said "fine, let's just do it now." And he says "I don't even want it now." So I said let's just do it later then I guess. & he said "you're just saying that and you're gonna say no later. It pisses me off when you tell me one thing and do another".

The whole rest of the day was so shitty. He was snappy and kept bringing it up. I just shut down. I understand why it bothers him when I dont want to have sex, I really do. But I also hate when I feel like I don't have a choice. Half the time when we have sex i just feel like crying bc i just said yes to avoid an argument. Im so sick of feeling this way. I just wish I had the guts to leave. It would be better for both of us