Here's the thing, ALL relationships are selfish. Yes, all of them. If you are getting zero value from a relationship, you will probably lose interest and leave. (Unless you are convinced they're the best you can do).
As an example, you could be dating a guy who looked attractive to you, had ambition, confidence, a good career, and everything going for him. Then one day he loses his job, falls into a depression, lets himself go and stops trying in life. I'm guessing you would lose any attraction you had to him, and would consider moving on if he didn't turn his life back around.
So the real question is, are feeders only interested in sexuality to the exclusion of all else? Well, some are and some aren't. Just like the general population.
Some people want to have relationships that are only physical. Of course if the sex stops being good, then there's nothing left keeping them together, and they'd both be happy to move on to the next casual relationship. As long as they're both honest about what they want, there's nothing wrong with that. Same thing with some feeders. (And no, I don't think most feeders are dishonest about their intentions.)
Some people want to settle down and spend the rest of their life with someone they love and raise a family together. If the sex were to end, it might not be as big a deal, because they would still love each other and have the life they built together.
It's no different for feeders. Just as I've heard stories of feeders taking off once the gaining stopped, I've also heard stories of feeders who were supportive of the weight loss because they wanted to be a dad more than they wanted to be sexually satisfied.
That being said, fulfilling sex is kinda important for every relationship. Nobody wants to live their life with sexual frustration. For some feeders, hearing "I want to lose weight" is the equivalent of saying "We should both try chastity together".
6 years