If you are constantly wondering if there's someone better out there than your current love, then it's quite obvious that something is amiss with your current relationship--mainly, that the original poster (Lisa) is blatantly "settling" for someone she's not completely happy with.
I myself am not a fan of settling at any age, but at 16 it's ridiculous. Although it's not my style to settle for someone less than what I need, desire, and am happy with--I can understand an older man or woman settling if they are compatible with their current significant other. A 16 year old has all the time in the world.
She needs to examine herself and find out what makes her happy, what she wants and needs, and what she is willing or not willing to compromise on, and then continue dating. She can date and have fun while she's looking, but there should be no question of making a serious committment with someone she is so obviously not happy with.