GRBYP - I can't speak for other men. I'm a bloke, but then I'm one who chats on the relationship thread on mumsnet so I'm possibly atypical.
From my experience, I don't generally sleep with someone without actually wanting it to turn into a relationship - but the problem is that once that's happened, I can just.. go off them. Not that I intend to. Some of it is my perception but there is a definite change in the way women act, like they suddenly feel comfortable letting their inner-weirdo out.
Examples of this are:
Ramping up the text messages from 5-10 a day to something like 50
Sending me 5 emails overnight to wake up to, with youtube clips of Craig David & Michael buble songs. Not my cup of tea, especially when I'm working out if I have to pretend I'm interested in them?
Telling me not to worry, my kids should be able to put themselves to bed by now, can't I stay and talk for a bit longer (this from a woman with no kids after I said I couldn't talk on the phone because it was my kids bedtime, and we'd been on the phone for a guilt-ridden half an hour while they were watching TV)
Telling me I was too close to my mother and that was a bit weird. To clarify, I generally speak to my mum once a fortnight, which for her seemed weird because she hadn't spoken to hers in a year.
All of these things, which if mentioned on a first, second or 10th date would put me off a woman, tend to come out fairly quickly after DTD. Sometimes within a few hours. And it is just very unsettling that someone I thought I really liked turns out to be possibly unstable or selfish or just weird.
So it's not just me, it's them.
Maybe a bit of me.