Playing the field is all well and good: heck, part of the joy of life is keeping your options open. Even so, you should make an effort to act honorably at all times. So if you've got a ton of choices, please remember that other folks are involved too. You don't have to show all your cards by any means, but if it seems like someone's getting more invested in you than you are in them, it might be time to clear the air.