Tieme32:
do you think that means she would like having sex with another man more, that it would be better?
Yes, I think that was her hinting at that rather than coming right out with it so as not to hurt your feelings. You might not be that bad in bed, but maybe she likes the idea of having sex with someone else, for a change, a bit of variety. Your post has made me think about something my wife said now, before we actually took the plunge and were talking about her doing it and role-playing it in bed. Her comment that I "probably wouldn't be able to handle it" if I were to be there and witness her being fucked by another man may well have been her saying exactly what your girlfriend has told you.
One of my ex-work colleagues who'd been after my wife's pussy for years and finally succeeded in getting her into bed boasted to me how she'd enjoyed being fucked hard and how vocal she'd been whilst they'd been doing it. Our love-making was usually gentle and considerate and she couldn't make too much noise in case the kids heard us, so I suppose at his house she could let herself go more. Although my wife told me that his cock was half the size of mine, I'm sure she liked his muscular physique and tattoos, neither of which I have, as she'd go and see him whenever she fancied a good pounding for 2-3 years, until he moved away.
Peter C