Is this normal?

I am in a long-term relationship with @deadgerbil Recently I've been noticing that when it's time to go down on him, he has a noticeably bad stench. I mentioned it to him and also saw that the outside of his underwear seemed to have skid marks on them...???? He confessed that in order to save on laundry and water, he wears one side of his underwear for a few days before flipping them inside out and then continues to wear it for a couple more days. I was shocked and honestly disgusted. I even considered breaking up with him. I've never really noticed that he had poor hygiene so this came as an utter shock to me. I tried to tell him he needs to fix this and change his underwear daily, but he wouldn't listen.

His excuse is because he's a broke college student." Ew.

just have to ask, is this normal? Should be absolutely disgusted and turned off by this? Should I break up with him? really need help on what to do