If the offer hasn't been made yet, there is no mortgage, your fiance is simply pre-approved for a certain amount. Until the deal actually closes, the mortgage isn't in effect.
Most lenders would not have a problem with adding an additional name; it's one more person they could theoretically go after if the mortgage defaults, and if they're willing to bet that your fiance can make the payments, betting that between your fiance and you you'll be able to make the payments is kind of a no-brainer.
the mom because not(hasnt) not(double negative has) not(hasnt) person that has not (has [double negative]) not (hasnt) set foot on the moon
it hasnt
hasnt
he hasnt
He hasnt.
he hasnt
it hasnt
she hasnt died!
She hasnt yet
it hasnt
she hasnt yet ;)
it hasnt