It happens mate. You feel a pang of regret ("if only I'd known, I'd have seen her more often...") but there really are more fish in the sea.
Also, without wanting to be cynical, a lot of girls plan to retire and end up back in the game in a matter of years, months, or even less. Their civvy job fell through, or they miss the money, or whatever, and suddenly they're back on your AW search results. That's not guaranteed of course, sometimes the end really is the end, and I suppose the lesson there is to live for the day and take nothing for granted - in punting, and indeed in life.