Due to my extremely bad credit I couldn't go on the mortgage. So it is solely in his name, although I will be paying half the payments.
We have been advised to take life insurance which my fiancé will definitely be doing, but if I take out life insurance also to cover the mortgage if I die, will it pay out if I'm not actually on the mortgage?
As I don't see the point that if the worst happens they won't even pay out to cover it.
Then just buy a 30 year level term life insurance policy naming your fiancé as the beneficiary to the life insurance policy. That way, if you die, he will get the money and can use it as he sees fit, which may include, paying off the mortgage on the home you share with him.
A level term life insurance plan is very affordable compared to other types of life insurance, it has a premium that stays the same each year for the term (duration) of your policy, and the amount of life insurance remains the same each year of the policy, for up to 30 years.
So, if you have a 30 year mortgage on the house, you may want to consider a 30 year term life insurance policy naming your fiancé as the beneficiary.