So long as you maintain separate accounts, one spouse's credit will not impact the other spouse's credit.
The exception to this rule is in community property states. Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin.
In a community property state, if an account goes into default, even if it's an individual account, the adverse TL might be legally reportable on BOTH spouse's CR.
If either you or your betrothed, once married, apply for an individual credit account of any kind, should it go into default then it definitely can get reported on both your CRs. The account was obtained inside the martial community (after marriage) so the bad TL belongs to both. Both spouses could be sued, even if you later divorced and regardless of what the divorce decree said.
Because you are going INTO a marriage, and don't yet have any joint accounts, should one of your existing individual accounts go into default in the future after you're married, as the marital community benefits then it becomes reportable on both CRs. If it goes into default 2 days after you're married, it probably would be tough to prove the marital community benefited from this account. However, I suspect most creditors are going to exercise caution, and most might not know about community property. You'd likely only run into this with a partially nasty CA or a collection lawyer who knows the community property statutes and caselaw.