Speaking personally, when I first started on dating sites back in 2009, I thought 'I'm a catch - I'm attractive, intelligent, good job, decent personality - men will be lined up'. I knew a few people who'd met their partners online (for some it was the 1st or 2nd person they dated) so I thought it would be easy. It wasn't.
After 4 years of men only ever wanting me for sex (and getting an immediate knockback from them when I said I wasn't interested in only that) I honestly started to question my worth - it was fine me thinking I was the bees knees, but when you can't meet one man who thinks you're worth more than a ONS, even the blokes I didn't find attractive saw me as purely a sex thing, it makes you start to question it all. Do I think too much of myself? What am I doing wrong? Why is it so easy for other people? Why can't I get what I think I deserve?
In that time, the closest I got to a relationship was when I 'dated' a teacher for a while. When I say dated, all our meetings were at his house (he had an injury which meant he couldn't leave the house for a few months). And our encounters basically involved me going there, we'd talk (actually decent conversations, he was on a similar wavelength to me, so there was lots to chat about), I'd 'service' him and go home. Once he was back on his feet and able to leave the house, I never saw him again. At the time I was so glad to have met someone who I could actually have a discussion with, but looking back it really wasn't much better than any of the others. I got very little out of it physically, and clearly whilst I was suitable for him to pass time with whilst he was housebound, he didn't view me as actual girlfriend/ dating material. He met someone else soon after and they were married within a year, so it wasn't like he wasn't looking for a relationship, he didn't want one with me.
That kind of stuff fucks with your head, it really does. And inevitably you end up wondering why this is all men want you for, when no one seems to want you for more than that.