Wow.

Not the most straightforward of situations.

Your partner could get six months to stay here (if you are from Britain) on the tourist visa under the US / UK Visa waiver program but then for the baby to be born here as your wife would not be covered under the NHS it would be pretty damn expensive.

It would be worth getting in touch with the home office and seeing if there would be some way to apply on compassionate grounds. However as it is in their interests to not have a large amount of non British citizens taking up their hospital beds your best bet may be to find out off your wife's local citizen's advice if there is any way to have your stay extended on compassionate grounds.

Obviously your wife's divorce would have to go through before you began applying for the fiance visa

 

I think this approach is not without risks. If your wife is visibly pregnant, the immigration officer may ask questions about that, and he may even refuse the tourist visa. I don't think this is a likely event, but it is a possibility.

I agree. I think you can avoid a lot of problems by being completely honest, but there is no guarantee that the decision goes your way. Your case is a perfect example of "compassionate grounds", if you can produce the necessary proof on paper. If your partner has started the divorce proceedings, a copy of that would go a long way. The other thing you have to prove is that the child is yours.

And remember that there is also a legal view of fatherhood (which can be different from the biological one). So you have to make sure that the divorce goes through before the child is born. And for the application, you need to demonstrate that you want to raise the child, and that you can support it.