Rio,
It sounds like you only learned to be a victim. And when someone is kind at all as mentioned above, you open the door, giving them some kind of value. Preditors don't come right out with who they really are, they DO come across as NICE and CARING.
Preditiors try to give good advice, they appear to be caring and concerned and they even talk about how unhappy they are and how being with you could make them happier. All this is done to make you think that you have value, something that you are questioning (especially at your age). But make no mistake, it is their own needs that are important to them, not yours. Even the fact that this man is married is showing you that he is not thinking about his family, his own children, he is only thinking about HIS needs.

You have to learn the WARNING signs of these kind of people. You don't have to live your life as a victim over and over again. You should be looking for someway to educate yourself and work on yourself and not stay in a position where you NEED to be taken care of somehow.

Your friends do recognize the warning signs, they don't have the victim mentality and they can see that you are heading down a dangerous path. Sometimes that is also a good way to see that you are not seeing the truth.

Open Eyes