I did, 25 years ago. He was a really nice guy and we were in love, I had a dc and this guy was with us from when dc was 2, when dc was 5 I was advised not to go put my body through another pregnancy (chronic illness since 12), my lovely bf was born to be a dad, he was wonderful with my dc and his nephew and we had planned two more kids but I knew he'd tell me that my dc and I were enough and we should stay together, get married etc but I couldn't do that to him so I lied, told him I'd fallen out of love and wanted to date others, he was heart broken but is now married with two dc so I still believe I did the right thing.