I have been very good friends with a girl since college (so roughly 8ish years).
We used to go out once a week to have drinks or dinner ... it got a little less when she moved 45 minutes away but it's just one of those things.
We went out for a mutual friends birthday over a month ago now and I asked her if she was free on x date (2 weeks from then) to go out for a drink and she seemed very reluctant and didn't seem to want to give a yes or a no.
I casually mentioned to her was she saving up for something so didn't want to spend money on nights out and she stated that she wasn't, and then said - and you know I'm not single anymore right? (She had been on 2 dates at that point but they are now in a full blown head over heels relationship)
I never bothered to mention the night out again and haven't bothered to ask her out since and neither has she. I go out with my friends and have a good time regardless of what their relationship status is and I feel sad that obviously I'm only worth going out with if she is single too.
However it's pretty obvious this will come across as me being jealous. I'm not, I'm genuinely happy for her but I don't want the rejection of her saying no to me if I asked her if she'd like to go out - because it felt pretty humiliating before.