Im not offended by the idea that someone wouldn't be attracted to me at my current size, but might if I were smaller, I am not attracted to men of a similar size to me, you can't MAKE yourself be attracted to someone if you're not.
On the other hand, I have always been fat, overweight, obese... as an adult I have never not been.
I have not struggled to find a partner since the age of 17. Not once. I have been single for around a year twice since 2007, out of choice, because my mental health was very very bad, but otherwise... nope, not an issue and it is only my current DP who is overweight and he's got that way after 17 years together (plus, addition of driving licence and vehicle and him giving up cycling!). The rest have been generally tall and slim!
I think a lot is down to behaviour and attitude, and of course much is down to the type you're attracted to as well - if your thing is highly sculpted gym-addicts who eat clean and run everywhere, the chances are they're not going to go for a very overweight or obese partner.
I've also never gone out LOOKING for a partner - I have met them all in the course of doing other things, which is probably another reason I have never had an issue, they've got to know me for me, rather than selecting a person based initially on appearances.