Melatonin can really help the jet lag - I highly recommend it.
Your MIL sounds toxic - even if she's dumb enough to believe that your H is truly happy now, WHY would she feel the need to relay that information to you? I'd steer clear of her.
For now, your job is to let go (my favorite phrase from this time - "Let go or be dragged") and to dream up a fabulous new life for yourself. If you can find an American movie called She Devil with Roseanne Barr, watch it! Sit down and make a list of 100 things you would like to do or achieve if you new you couldn't fail. Read midlife success stories of women entrepreneurs. Get inspired! Take on new things. Get a new haircut. Dye your hair pink. My feeling at this time was, the worst has already happened, so why be afraid to take risks?
Imagine yourself coming back to New Zealand in a year, stylish, svelte, successful - how great would that feel? Write a book, start a company, climb a mountain, play in a rock band. Your H and his opinions of you are no longer holding you back. Your motherhood obligations are no longer sucking up all your time. This is time to become the YOU that you are meant to be.
Be adventurous. Take a job working in a resort. Or go to school and get that degree you always wanted.
What are the dreams you had when you were young, that you put aside for marriage and motherhood?
