Your friend got engaged not for a two year ago one night stand but because of how the relationship between her and her fiancé developed over those two years.

It's not a one night stand if it resulted in a lasting relationship. Dont give up! Your time will come : )

Seems like your friend got lucky with what she expected was a one night stand that turned into more. But generally you seek what you find. If you’re out looking for and accepting one-night stands, don’t be surprised if that’s all you get. It’s not a problem if that’s all you want, but you cannot complain about not finding something when you’re not likely looking. If you’re looking for something lasting, make sure you’re actually prioritizing meaningful interactions rather than casual hookups, communicating about expectations, and looking in places where you’re likely to find someone with compatible values. If you’re simply taking home the first person you find mildly attractive at the bar or on tinder, you’re not likely to find what you’re looking for.

well you're not bitter at all