LL - I would take MIL up on her offer and drag H out to a nice dinner. Make it an opportunity for you to shine, LL!
Since you're going to shop for a couple of bathing suits, offer to show them off for H after the kids have gone to bed. Who knows, it might lead to something!
Keep looking for the little things, LL. And I hope that you and the kids have a safe and happy trip down to FL!