Lou............ I have to admit, your plans have me worried. While I love the idea of a vacation, I'm worried because you have worked SO HARD to gain some financial stability in your life. Your husband makes good money but he's still in debt, correct? In fact, part of the problem when you split was that there wasn't any real savings because of his poor money management. Now it sounds like he's pulling you along on another bad financial decision.
When he makes so much more than you, why are you footing half the bill for this trip? How is he planning on paying his debts during this time? Do you have enough to travel for four months WITHOUT tapping into the money set aside for renting and furnishing a new place?
If, God forbid, you embark on this adventure and then realize that the new relationship isn't going to work, will you have enough savings to tide you over until you get a new job and place to live?
Sorry to throw cold water on your plans, but it just sounds like an old pattern of going along with his bad financial decisions. I'd hate to see you struggling again in a few months with no savings. And the exhaustion you feel from your untreated thyroid disease is not going to get better until you are treated!
Is there a way to take a trip without completely wrecking your finances? How about renting a caravan, instead of buying (so you don't risk getting stuck for a large repair bill) and going for just a month (instead of four) then getting serious about looking for work and a place to live (which might easily eat up your remaining savings by the time you find a place)?