What's love ?

I have been with the same person for 2 years almost. He has been my first everything! We've broken up a couple times but always mange to find our way back together. Lately I've been catching myself fall deeeeeply I love with him again to where I feel like half of me is missing if he's not by my side. I'm scared of falling in love or getting attached with him again because it always gets messed up. Then I end up being completely broken so then I find myself trying to find things wrong with us when there is NOTHING wrong! He's amazing I love him so much But I don't know deal with loving someone so deeply because he's all I think about. Opinions? Advice ?  Story's of past relationships? I just need to know I'm not crazy and that there's nothing women that have or went thru something like this