My Dp is very over weight. I don't know what he weighs but he wears an xxxl/50inch waist and has managed to break 2 beds in 6 months by sitting on them!
He was much bigger when we met. He's a lovely bloke but quite soon after we met we talked about how his weight would affect our relationship. It sounds awful but sex with someone that big is rubbish. You can only use one position (woman on top) and the more over weight a man is, the smaller things get. Plus, hygiene was an issue because although he washed, there were sweat and hidden bits that he couldn't see well enough. I couldn't see myself in a long term relationship with such an unsatisfying sex life even it was changeable.
And I didn't want him to drop dead of a heart attack, or to have the extra expence of his take aways, extra plane seats, specialist clothes, etc.
It caused him problems with getting dressed, putting socks and shoes on, and getting up from seats.
He didn't have a medical reason, he just over ate and ate the wrong foods.
And I didn't want to enter into a relationship with all that going on.
A year later and he's doing great, lost 6 stone so far, and can buy a t shirt from a shop instead of online, our sex life is improving, he's joined a gym, we don't have fizzy pop in the house (that's made a huge difference) and have a take away once a fortnight. He doesn't drink and walks for over half an hour every day. I respect him for it. He's also happier in himself and more confident. It had to come from him though, I suppose having a relationship was his incentive.
I wasn't as blunt to him as I was here. But talking about it helped.