relationship advice, losing interest too quickly in a relationship?

i've tried dating and stuff but it always seems to end very shortly due to my lack of interest.. i could be in love with this dude and then like 2 weeks later all my feelings will drop and it doesn't bother me.. everyone said when i was little i was going to be a heart breaker and i guess its true.. and when im Just talking to a dude that i like its very hard for me to open my feelings and let him in.. and i always run away ... im asking could this be a possible curse of love? or something? can someone help me out???