Crikey! I think you need to remind him of the days he made you delete the males.... and tell him if he doesn't stop with this woman you'll jolly-well make new contact with yours if you can.

Why not? To me, it's fundamental in a relationship that both work to the same implicit or explicit ground rules. When this guy tied up with you he created an explicit rule - no room for ambiguity or misunderstanding.

I mean, fair's fair. Besides, his old flame claims she loves him but why come back after all this time? What's happened in her life? What is she really after? We all do a lot of "moving on" in 50 years i imagine so neither she nor he will be the same person. I mean. I'm not the same person I was 20 years ago, head full of teenage romances and stuff so...50 years?

Best of luck dealing with this. If your guy is worth YOUR keeping then he'll work to the rule he created!