I know exactly what my moment was here.
When I first got with DP, about 3 months after we got together, there was a really nasty situation with a woman he used to know.
Basically they were good friends for a while, they both had feelings for each other, but she messed him about, wouldn't go out with him properly as a couple, and in the end told him he should look for someone else.
The second he FOUND someone else (i.e. me), even though it was quite a while after she'd told him to, she immediately started sending him ridiculous texts like 'it should have been me' and saying that if he ended things with me, she would give him everything, her heart and soul, and she would move in with him.
Understandably this unnerved him as he'd had feelings for her for so long, he hadn't known me that long and had no idea whether our relationship would work beyond casual dating, and for ages she was all he wanted.
He was honest about this and told me it'd thrown him. I was gutted as I loved him even then, but I sat with him and talked it through. He came to the conclusion that this woman was saying what she was because she wanted to control him, and he did the very difficult thing of telling her not to contact him anymore .. which she ignored, and continued messaging, but after a couple of months we never heard anything from her again.
Three years on and we live together and are very happy and running a business together.
What he DOESN'T know was that while we were sitting there talking things through, I had made my mind up that I would tell him the next day that we were over, as I couldn't deal with the upset this was causing me. He made his decision before that though, so I never got the chance to end it, and I decided to give it a go - but also that if this happened again, I'd be gone. Luckily it never did.
He doesn't know even now how close I was to ending things, and if I had, we wouldn't have all of this now.
The ironic thing is that me and this woman had quite a lot in common so if she hadn't behaved the way she had, she would probably still have me and DP as close friends. But hey ho.