If you have a joint debt and only one of you goes bankrupt, the other person named on your credit agreement will become responsible for the whole amount of the debt. This person will then have to make arrangements to pay the total amount back by themselves.
This situation wouldn’t happen if you both went bankrupt. However, if bankruptcy was confirmed as the most suitable solution to deal with your debt, you’d each need to apply individually for your bankruptcy and both of you must pay separate bankruptcy fees.