For me, there is a difference between being in love, and being in love with the "right one"!
I have been in love a couple of times - all very nice guys, but for some reason or another, I never felt they were "the one."
When I met my DH, something immediately felt different about him. It's not that he was the first one I was "in love" with, but with him, there was this absolute sense of calm, of companionship, of trust and respect.
When I met DH, it was the first time that I often put my needs second and his needs first. I knew I could do this because generally, he put my needs first.
Also, the genuine respect and admiration I have for my husband makes me fall in love with him a bit more each day. I think that respect is such a necessary part of being truly, deeply in love.
One of the nicest things about being in love is the wonderful assurance and comfort in knowing that everything you feel for that person, they feel back for you.