Yowey, my first relationship was with (to be incredibly blunt) a really fucked up boy. I had just turned 17 (May) when we started dating, all of mine and his friends told me to leave him be but I didn't. His mother was an alcoholic, his father had a degenerative disease and was an angry fuck, his uncle was a hardcore scientologist and his grandmother was in the late stages of a degen disease (all of these were very very relevant to our 'relationship' btw!). In my case it didn't end so well.
After a year I realised the effect he was having on me, bringing me down, making me lose all of my friends, refusing to let me study so I was therefore failing all of my subjects, refused to let me go home even really, went home for one night a week and even that was a hard deal. He was very depressed as well even though he at first said he wasn't, I was constantly comforting him, and he emotionally blackmailed me into having sex with him most of the time, though I didn't realise what exactly he was doing at the time I knew that I didn't want it.
I tried to break it off with him after Christmas but he threatened suicide that time. Second time was my 18th birthday, he turned up at my house at midnight and was a jerk to my entire family, tried to break it off with him then, threatened suicide again but I refused to go with it, then he refused to leave me alone, wating outside of my college for me, turning up at my house and sitting in his car outside for hours on end, pretty much stalking me. I got back with him just to shut him up and also because I had no friends left. I ended up finally leaving him after 18months of it, I was pretty much ready to kill myself just to be out of the relationship by that point.
He ruined my life, my confidence, my relationships with others, my chances to go to a decent university, my dreams and ideas for the future, etc.
Thing is, I never listened to my Mum. I refused too and she pushed me away somewhat by trying to intervene. I had to make my own mistake that time and I learnt a lot from it. This Christmas would be two years since I broke up with him and my life has changed completely. I still have relationship issues, I still have flashbacks of him forcing himself on me when I'm trying to get intimate with my OH and I'm still screwed over by it, but I've moved on with my life, am finally doing what I want to do and am with a really lovely guy who cares for me like he should. If I never made that mistake with my first boyfriend I never would be where I am today, and I just would have made that mistake later, and possibly with very different results. I dated a few times last year but I just couldn't stick with them, then in October I started seeing a guy and we had to go long distance due to work commitments and I feel ready to have a proper relationship with him come Christmas when we both will start working together
Your daughter has to make her own judgements on this and all you can do is stay by her side no matter what she says to you (because I know that I was quite horrible to my Mum during that time!) and let her make her own mistakes. If it weren't for my Mum I wouldn't be where I am now, she realy did stick by me in her annoying, Mum-like way ;)
Sorry for the rant, I just wanted to give you a bit of detail, it's still fresh in my mind obviously and sometimes I need to get it out