Examples - she puts on weight, starts ageing, changes her hairstyle or stops wearing makeup when she looks better with it.
Most Helpful Guy
"starts ageing" How dare she... I'd leave a girl if she did that...
If she put on a significant amount of weight (so that it was a health concern and making every tasks difficult) and was unwilling to do anything about it I might consider leaving her. If she got a bit chubby or was overweight but agreed to work on it I don't think I'd leave her.
I guess if she shaved her hair off (or did something equally hideous) I might be a bit disappointed, but would probably stay, depending on how long we'd been dating.
I'd be pleased if she stopped wearing make up, even if she wasn't quite as photogenic.1