The last one. We were together 8 years, with a small break, and had a son together. We were ill-suited and didn't really make each other happy despite our best efforts, but stayed together anyway. In my case it was for our son's sake. In hers, I suspect she kept thinking I'd change to suit her more. Over the last 6 months or so she started going out with the girls a lot, particularly one single friend. I had my suspicions but tried to trust her anyway, until one night when she apparently forgot I'd come out with her this time and openly and obviously flirted with a couple of guys right in front of me. I went home, then went back to pick her up later, only to find her walking arm-in-arm with yet another guy. We fought, I asked if anything similar had happened before, and she said no. However something seemed off, so over the next week I went through her email accounts (not proud of this, but it beat not knowing), and let's just say she didn't take the opportunity I offered to come clean.

The infidelity hurt a lot, but worse was how easily and casually she lied to me over and over again. The person I'd been struggling to build a life with just wasn't who I thought at all. It felt more like grieving for someone who'd died than a break-up, and since we have shared custody of our son I still had to see her all the time. In hindsight, I missed a lot of red flags.

But there's a happy ending. Our son is a lot happier now that he's not surrounded by arguments all the time, I don't have to out up with constant tantrums, impossible expectations, and the occasional assault, and a little over a week ago I got engaged to the most wonderful, beautiful, fascinating, intelligent, loving, funny, and crazy woman I've ever met. I'm a fairly cynical person, but she makes all the love songs make perfect sense.

Would I take her back? I wouldn't piss on her if she was on fire and allergic to piss.