Why am I not horny enough before sex ?? Help me !

Oka so I've dated girl and guys before . I also got touched sexually and verbly by my moms exs husband . Idk if that had to do about it but it happened .Girls wasn't really that great , and guys weren't either . Until I started dating my boyfriend now . Never once had The BIG O while having sex with a man until him 😍🍆 . BUTTTT is so hard for me to get into sex in the beginning , I never want it unless he starts it . I use to start it all the time when I was younger , but now I don't even care for sex . But once I'm getting fucked I'm all good lol . I wanna be able to feel like doing it , think about it all that stuff lol . I wanna be able to just climb on him and be already wet like a rain fall lol .