Friend/relationship problems!! help please?!?

kso, i'm best friends with this guy named joey. he's really sweet and all, but i'm not sure i'm looking for anything to serious. you know how people say "can you imagine marrying this guy, or spending the rest of your life with him?" well i think i can. and i pretty much have a crush on him. he likes me also, and he asked me out. of course i said yes. but when we were together that time, i didn't feel anything!! no spark at all, so i ended it cause i thought it was to weird. now i like him again! maybe a little more then before?! what the heck is wrong with me???? i'm afraid if we go back out that i wont feel anything? i'm so confused. help!!