I agree esp with the bolded. And for me in the beginning I can't stay physically separated from him for too long and he feels the same way. I want to see him ALL the time, and when we've spent the the whole weekend together, when I go back home for a couple hours, we start missing each other..he'll text me and tell me to come back now, lol. I'm sure it's different when you live together. I've never lived with a guy I've been in love with so I'm not sure how that goes. I want to touch and hug, kiss and cuddle with him all the time (and I normally hate all those things).
I'm not sure when I realized it but it was gradual. I think he was in love with me early on but didn't tell me because I definitely didn't feel the same way. He's amazing and will to do pretty much anything to make me happy.
But being in love and being compatible in a long term relationship are very different and separate for me. I've been in love before with men(2) that are not compatible with me..and that sucks! I still love them and not any less just because we have differences. I just can't be with them. Current guy and I are so similar on so many things(values, views, habits, etc) and enjoy the same activities that it makes it even better and will hopefully make the relationship last longer.
Oh yea, and being in love is the best high ever.