My ex became a gym bro after getting married. Two years into it he asked for a divorce because he was upset I did not know how much weight he was lifting in the leg press machine. Some months before he had "banned me" from going with him to the gym because I did not match his vibe, so when I returned I was kind of doing my thing and my own routine, but not focusing fully on him was apparently the wrong move.
So well, that. Narcissist type. Obviously he had a new girl immediately after, but the reason he gave me about the weight was just so petty.