Basically what several others have said, but just want to emphasize that often when the timing is wrong, something else will be wrong at a later time that will make it clear to you there was no way you could have brute-forced that relationship to ultimately work well for both of you. I’m happily married with no regrets right now, but I’ve taken comfort before in loving the ones who have “gotten away” from afar by imagining how happy they could be with someone else—because if I truly loved them, wouldn’t I want what makes them happy, even if it’s not with me? And what a gift to truly love someone even when they can do nothing for you in return… it says something about your capacity for love, even if it exists alongside pain or loneliness.
(that said, yes it can hurt like hell and it sucks)