He says I'm the only one, but my friends say he's playing the field.
Then go out and be utterly promiscuous and play the field.
Whether you choose to play the field in high school or you find your high school sweetheart right away, dating is fun.
Immature, uncommitted people will "reason" away guilt and play the field.
In relationships, Monkies does not like to settle down with one mate and would rather play the field until they find the "one".