Life is too short for shit sex.
Oh, this in spades! It knocks your confidence because you can't help but wonder if it's you; it's demoralising because it's supposed to be, in part, what a good relationship is about; and it's just a bit dissatisfying!
slamdunk I think your mental attitude towards it all is key. Due to a pretty crappy year, I lost my parents and husband in the space of a few months and had a choice to either draw a line under it and start again or wallow. So I drew a line. About a year after we'd split up, I had a couple of mums from school tell me that they'd initially felt really sorry for me at my marriage breaking down but were now secretly a bit envious of the life I was carving out for myself. But it's all about how you approach it.
I'm happy with telling people that I just haven't found anyone worth not being single for. They generally ask me out of curiosity rather than pity - after all, on paper I look like a reasonably good 'catch' and, whilst no one is ever going to accuse me of being beautiful, I am attractive (if unconventionally so - according to my son!) I think I'm 'quirky' rather than 'pretty'.
Much like your friend, I'm not afraid to ask men out - the only men I've dated at all since being single again have been because I asked them! I've got past all that being shy and worrying that I'll make a fool of myself if they're not interested. I tend to think nowadays that it's flattering to know someone is attracted to you even if you don't feel the same so I'm not bothered about rejection.
But, generally, I don't think men are interested. Like I said before, I get the usual amount of interest from married men who are just looking for a bit of fun on the side
but single men are always looking for someone else. What can you do?!
SimplySteve I play bass in a rock band. Fucking love it! 
Notcontent That's it exactly. I'm not drowning in a mire of self pity and loneliness and I see enough of other people's dysfunctional relationships to know that it's not all a bed of roses but, like you say, sometimes something just triggers it.
The other night it really was looking around and seeing all the people I'd spent the evening with cosying up with their partners at the end of the night and leaving together whilst I headed off to the car on my own... again...