S.,
Watch out. Don't forget your lines or boundaries or however it is you think of them - don't think in terms of "doing anything" to make it work out. I got back together with my first love after an 8 year split. We were married almost 10 years and now we're divorced.
I would have done anything to get back with him, I did everything I could think of to keep him, and finally, after 10 years, our split was due to issues we'd never worked out in the first place and me coming to him as one who'd made the mistakes in the past. We're friends, now, but tossing self-respect aside to win someone over will make you realize a) they aren't worth it and b) you are worth more than that.
On the other hand, I LOVED him. Loved him, loved him, loved him and I don't feel my life would ever have been "complete" if I hadn't given "us" a chance.
God Bless You!