Anytime people get into relationships it is because there is some type of need that needs to be met.
You may want companionship, someone to go places with. You may want affection. You may want someone to help pay the bills.
Whatever your reason, don't use a person.
If you know that this person is not the one for you, then don't even start taking things from them. Stop before it gets any further.
Always remember, what goes around comes around.