He has a bad rep, but I still like him!

I am a 23-year old woman and have been in love with a guy from my college for a long time. He has a bad reputation because he has been dating a lot of people and always breaks up with them after a few months. My friends say he just uses them and doesn’t treat them with respect, but I can’t help how I feel about him. He recently sent me a friend request on Facebook and has been chatting with me for a few days. He asked me out for coffee, and I accepted, but my friends keep warning me about getting too close to him. They think he will hurt me eventually, and I respect their wishes, but want to see him, nonetheless. I am prepared to be hurt, but still want to know him better. Maybe I can change who he is. What should I do?
If you believe you are going to get into a relationship to change someone, that operation is probably doomed to failure. It makes more sense to get into a relationship with someone you want to be with because you appreciate who they are, not because you believe you can change their personality in some way. If you are prepared to be hurt and accept that this may not work out, you are an adult with a mind of your own and are perfectly capable of making that decision. Think about why you want this though, and what you believe it will do to your self-esteem. Being in love with someone is great, but only if that love and respect is reciprocated.

I want to break up with my girlfriend, but she is going through a bad patch, and this may just make her more depressed. Being with her is really bad for my own mental health though, so I can’t figure out what to do. Please help.
If this is affecting your mental health, you aren’t in a position to help her and may probably make her situation worse.