If I joint my tax with my husband, will his student loan also affect me?

My husband has the student loan. And he couldn't repay it back earlier, so his credit is very bad right now, like he even couldn't apply for credit card. I added a credit card for him under mine. We definitely don't want his bad credit affect mine. So we still could take loans from bankers in the future for buying something like a house. Could I ask could we do tax return together, but still keeps mine credit not affected by his? Besides no joint bank account, probably no joint tax return, is there anything else we should pay attention to? If we do the above things, I should also needn't share responsibility for his loan right, no matter we are in the marriage or in case getting divorced? Thank you very much! Best, Wendy