I don't think its black and white, for reasons
@Bigpapa stated.
However, I do think it is super important that she maintains a nice body. I have no use for a woman that doesn't turn me on visually. Its the foundation for me. If I am not visually attracted to her, then I can't be mentally attracted.
I once let my exwife know I wasn't happy with the 15lbs she gained. I told her if I wanted to be with a fat girl I would have found me one to start with. She got in the gym and took care of the problem.
IF you bring it to her attention and she fails to do anything about it, then it shows me she doesn't care and Its like false advertising. Its a fake bill of goods. Not caring and false advertising are grounds for divorce. They know we are super visual.
I had a neighbor that married a hottie. 10yrs later she was a fattie. He quit having secks with her. She got the hint.
Never get into a LTR with a girl that doesn't have great genetics and or a work out program going long before you. Makes it easier for you down the road.
Do you think that girl is going to stay happy if you stop leading in the relationship? What if you go broke and mismanage your finances? She'll be wanting a divorce at some point. Both the man and woman have obligations they need to fulfill.