Good or bad idea?

I'm such an idiot when it comes to past relationships whether it involves with ex boyfriends or friendships. I was on facebook the other day and i had gotten an off line IM from someone from my past. This person has hurt me pretty bad and for the past year i havent had contact with them. We went our own ways basically but now this person has re entered my life. I dont know why i keep going back, i am not in love with this person but i want to see if we can try again being friends. Im not hoping for anything . My mom is so aganist this but i guess from where i am in my life, having drifting away from my friends, i'm  pretty much alone and desperate. Its sad i know, that is why i need advice, please i'm looking for some. I dont want to go back to the way i use to be letting everyone treat me like dirt. i just wished it didnt happen