Gimme a clue what to do...

I'm M31 my ex F25. We got together when she was 18 and I 24, the age difference wasn't a problem as we tended to bounce off each other - She'd be the mature one in parts of the relationship I'd be immature in and vice-versa.

Our separation after 4 years together stemmed from me ceasing to maintain my maturity in the relationship. I liked to go out for a pint with mates after work, she expected me to be home when she arrived home. These weren't late night drinking sessions, just a pint or two after work. In response to her not being happy with my behaviour, I escallated it, to the point where, say friday night came around and I'd just stay out till the early hours. I tried to encourage her to come out too, which we used to do. But she only even met up with me and my friends on a couple of occasions. My friends, mostly fellas, were always polite etc. they'd respect my SO as they'd expect me to respect their SO's.

Anyway, we split up 3 years ago, mainly because I thought the grass was greener on the other side. She moved back with her mother. I got into a relationship with a complete and utter psychopath, which made me realise how dumb I'd been, which all too late made me realise what I had. In the meantime she moved to Australia with the guy she was with before me and he ended up returning on his own. I friended her on Facebook after I ended the relationship with the nutjob, alas one drunken night I messaged her telling her how much of a dickhead I'd been and asked if she ever came back to the UK, that she might consider giving us another try. I received a genial reply, then nothing for 2 years.

All this time I've been torturing myself, hoping she'd come back, that I might get another chance. Then at the beginning of this year she 'friended' me again on Facebook and I learnt she was coming back to this country soon. Also that she'd visited a couple times in between.

I guess I want some advice on whether I should make the first move and spill my guts to her, in spite of her being back here previously and not saying a word to me? I've had other relationships in the interim yet I still can't shake her.