WHY DONT I LOVE HIM YET?? Help

So I've been officially with my boyfriend for 3 months now and known him for 5. I have been in love once before and I know the feeling of it. I was maybe around 15 years old and stayed in love with the guy until I was 18 so I know it was super strong, I couldn't imagine marrying anyone else or having kids with anyone else. We have cut all ties but for some reason I still think if he was to ever get a girlfriend it would hurt a lot. I really really really care and like my current boyfriend we get on like a house on fire and he feels like my best friend but I feel like I'm missing that spark sometimes. I don't even remember how I knew I fell in love last time... I think it may have actually taken around 8 months for me to fall in love last time so maybe I just need a little longer. I know the thoughts in having now we're similar to last time I was falling as I was kind of scared I was going to waste my time on someone. I honestly WANT to love my current boyfriend so bad as much as I loved the last guy, I just know he feels so much more for me right now then I do for him. Is there still time to fall in love or should I give him the respect and leave him so he can find someone better? I really really do think I will hate myself if iever let him go because he is so great to me, we haven't had one fight and the last guy I was in love with I think we fought non stop.

Please help, do you think I'm rushing into thinking about this? How long did you take to fall in love to the past or current boyfriend?