I want to leave him but I can’t.

I’m a 23yr old lady living together with my partner who’s 27. One morning I woke up with a text from home saying I must go there, so I went. As I arrived at home something inside me told me to go back and surprise my man but I hesitated and kept on fighting this feeling I had of me going back to our place but eventually I did. So I sms-ed him telling him I was on my way there “since I’m gonna be spending the weekend at home and I have an exam the following week. I thought I should just come by and pick up my books so I can study” but he didn’t reply so I called him and he didn’t answer and I kept on trying his phone but to no avail. Finally I arrived at our place. I opened the gate and went into the house. I could smell fresh soap and hear soft music playing so I shouted “bby! Bby! Are u taking a bath?” As I was busy closing the door, no answer. I walked into the bathroom no he wasn’t there, went to the room next door to it(our sleeping room) no he wasn’t there also I thought maybe his gone out. So I went down stairs to the other room to get my books and there he was naked and on top of another lady busy making love to her. My heart stopped beating for a while I swear! I was so shocked it suddenly went black and I couldn’t see a thing. I switched the lights on and ripped the curtains so I could see(day light, mind you) when he saw me he jumped up and the first words that came out his mouth “bby its not what you think” I was so weak I couldn’t say or do anything, after that lady left I broke down and swobbed until no more tears came. So basically after that day my life hasn’t been the same. I hate myself for staying with him but I am so inlove with him it hurts. I just need help to get over this hard time for me please guys I am not coping at all. Its been 3 months now and I can’t sleep at night I cry myself to sleep and at some other times I even considered suicide. So I drank so heavy one day and came home and locked myself in our bedroom and I slit both my wrists but he came to check on me and kicked the door open when he realised it was locked so here I am still breathing and hating every moment. I wish I didn’t love him like I do because his love is killing me and he doesn’t know it because I smile for him and pretend as if I’m fine. When I’m alone I think of killing myself but then my daughter comes to mind. I wish alcohol and drugs to never leave my body sober up so I won’t feel this pain no more. I pray and ask th Lord to help me but I feel better after a prayer then when I see him I feel like hating him and when I think about tht day I get emotional and yes his changed trying to show me that he loves me and that it was a mistake but I just can’t bring myself into believing anything that comes out of his mouth and I don’t understand WHY I can’t leave him when what he did to me is destroying me. I just don’t wanna live anymore