Yes, I moved out from my best friend and I's flat to move in with an ex. Even though we broke up a year later, I don't regret it. He was sort of a jerk for not being more understanding... I put plenty of effort into trying to see him often and hang out just us, he was too pissed I moved out to even try to be friends after...
I did, last week. The worst thing is i wasn't even dating the girl! He was! Flirting around with her every time, knowing i like her. For now, no regrets. But think its too early to make any definite conclusions about this.
I sort of lost my best friend for the 2-3 years before I got with my boyfriend. I didn't really do anything wrong that led to this 'break-up'. It was more like I just started hanging out with him more than with her. She had been my gym-buddy before, then he took that place, going with me almost every day of the week.
I don't regret it. Only after it was all said and done, including her sending me a break-up message over FB, did I realize she had never really been that great of a friend in the first place. She had essentially had a monopoly over me, hence why she lost it when he came into the picture. Needless to say, we sort of grew apart.