Wow Kym, I don't really know what to suggest - which isn't much help, I know. I think if I were you I would talk to Tiffany and make it clear to her that although you love her and your grandchildren, your health has to be your main priority and that you can do without unneccesary stresses.

From reading your example, I have a feeling that it would be tough on Tiffany too. She sounds like she wants to prove to you that she is a good Mum and is capable of looking after her children...hence her reaction when they came to you rather than her (albeit she was in the shower at the time). And to be honest, given the choice, she would probably chose for her marriage to have worked and for everything to be ok...but it's not and hence the fact she is turning to you.

As mother it is natural to want to help your children, and I understand that moving with you will be a nicer area, better hospitals etc, but that's not your responsiblity.

Try talking to her before you make any decisions. If it's a short term thing whilst she gets her feet on the ground and finds herself a job and a home of her own, then fair enough - but you need to be clear on this at the beginning.

It's a really tough decision and I don't envy you, but keep us posted.