In marriage, stuff you acquire during marriage is "common" no matter which accout you used. The same applies to debt. (Pre existing assets and debts are purely yours).

The common stuff then splits half half unless there was prenup or something.

This very much varies state-by-state (ignoring prenups and emergency med treatment as edge cases). In my marriage and state (FL) debts incurred by me remain my own. Wifey owes none of it. Compare with states that have community property or purchases made as tenants by the entirety.