My mum is Muslim, my dad Christian.
Take these things into account, especially if you have kisa:
If you have a son, would you agree on whether or not to circumcise to circumcise him?
Wouls you agree on whether or not to baptize them?
Is the dad adamant about halal food? If you can accommodate that, will the grandparents too, or will that be a source of arguments between you and your fiance?
If you and your fiance are of different origins, are you fully aware of the differences? Do you know about the expectations he has (in regards to your in laws, finances, living situation) and does he know about yours?
Are you happy to celebrate eid? Is he happy to celebrate Christmas?
What religious expectations are there for your children?
Wish you the best in your marriage.