KittyB, is it possible that your system clock was changed? That could cause what you are seeing. Also, if you pause the game often, that can affect the rate of emails, as well as events.
I don't think the system clock has been changed - I have it set to automatically update, and I think that happens pretty often, so I would've had this problem before. I have used the 'pause' option a lot in the game - I'd say for at least half my generations - and this is the first time I've had a problem with it. And it happens to coincide with reaching gen 31.
I will keep playing (well, waiting) and see if my person gets any proposals. If not, I will have to start again from scratch.
Thanks for the replies, all.