I need help accepting love

PLEASE help

My entire life my dad was an alcoholic & when I was 14 he passed away due to liver failure. The real changing point in my life for me was when I was 13 and my uncle (his brother) was taking to my mother right in front of me & my uncle said, “I can’t believe he’s just going to let this happen. I can’t believe he isn’t going to try to correct this.” And my mother said, “I know. I can’t believe he’s just giving up. He doesn’t want to see his daughter walk down the isle one day.” I feel like ever since that day, before my dad even passed away, that day is when my abandonment issues began. I have a crippling fear that everyone in my life is eventually going to leave me. Weather it’s friendships or relationships, I always feel like I care so much more about the other person then they care about me. And I always feel like in the end I’m going to end up hurt. These fears have consumed my life and I do everything I can to push people away. I don’t let anyone in. I don’t trust any real friendship I’ve ever had. And it makes my romantic relationships extremely difficult. I have a boyfriend now, and our relationship started off rocky. I couldn’t accept the fact that he wanted me and only me & I had this fear that he was just going to break my heart, as I fell in love with him almost immediately. I kept other people on the back burner and couldn’t ever truly give him all of myself. He was so hurt by that, we broke and up and got back together so many times I can’t even keep track anymore. While we were broken up he tried his hardest to move on from me and connect with other females, but we have always found our way back to each other. I feel like that has made my insecurities even worse. I just keep feeling like he’s going to find something better in someone that isn’t me. He does all he can to reassure me all the time. I’m not self conscious in the way that I feel I am unattractive or don’t have a great personality. I’m just insecure in the fact that I constantly feel like I won’t ever be enough for someone forever. And it just comes down to that fact that even my own father gave up on me, so why wouldn’t somebody else? I love my boyfriend so much and I want us to grow old together so badly. I just fear that if I can’t get rid of these insecurities it will cause massive problems in our relationship forever. It is the number one reason we fight. I just need help on understanding how to move forward. I’m now 25. I’ve been battling these insecurities for 12 years now and I just can’t seem to shake them. Please help me understand how to move forward. Please help me accept love.