Are you in the U.K.? If so, I’m not sure pre-nups hold much water, legally speaking.
As for dying before he does, you just need to make a will to state your wishes. Best to do it shortly before you are actually married, just in case, because if you didn’t and the worst happened (say on your honeymoon, or before you’d got around to it) then AFAIK your new next of kin dh would be entitled by law to a hefty whack of whatever you had.
I do know of a couple where this happened - dying only 10 days after the wedding having made no will - and the fall-out was prolonged and very bitter.
A solicitor would of course be by far the best to advise.