I logged onto my old email account for the first time in about, err 2 or 3 years tonight, as I was feeling slightly bored.
I came across an email from an ex, which she'd sent to me about 10 months after we broke up. It shocked me a bit. (Sent circa '05, so a few years ago).

"It’s funny, but not ‘ha, ha’ funny. Last night I dreamt you’d migrate back to her, your first. S. I knew you wanted her (them: all the people you ever, ever hurt me with) to stay close. I knew, and after months and months of freedom I dreamt a horrible dream again last night. So I thought I’d just check, and here you are, and there she is, and them, and all the rest. And so I have to laugh, you know. A bitter laugh. Because you lied (and lied and lied and lied – about her, about them, about yourself), you broke my heart and stole my self-worth and ed me over (again and again), and although you begged, you pleaded, you ‘changed’, my heart was in doubt, and OH, LOOK! It – I – was right."

I'd added my first love to a social networking site, and 10 months after we broke up, that "current" ex girlfriend felt the need to look at it, and bring it up.
I know that I shouldn't look back at the past, etc, but her wording of the email almost took my breath away.

Was I really that bad, all those years ago? Yes I was young and made mistakes, but so did she. I haven't heard from her since that email, and I've been worried about her on & off, as she attempted suicide a couple of times when we were together.
I've tried browsing the usual social network sites etc, but can't find anything on there about her. I guess I'm just trying to assuage my own guilt. I'm just not sure what to do.

I don't want this "apparent" bad side to creep out in future relationships, so I'm a bit off my guard.

Has anyone got any advice?

Best to live in the "now". You seriously can't do anything about the past, except learn from it. Anything beyond this moment is an unknown. Living in either will make "now" hard to live in. Make amends if you think you should. Mind you may be opening old wounds.

It's sweet that you are concerned and want to change. I think when dealing with relationships in the future you should remember the affect that you can have on people and be honest. As far as getting in touch with her, if it means that much, contact people you know have contact with her to check in or if you think it will derail her than just keep your distance and pray for her or whichever you choose to do, send her good vibes... however you do it.
My thoughts are that we do things when we are younger and sometimes older, that yes we regret, but as you mature and know better it is up to you to attempt to be a good guy and try not to do things that you know may be hurtful to others.