My boyfriend doesn't change his boxers often, is this normal?

I noticed my boyfriend wears one boxers for 4-7 days and he even sleep with it , So he wearss it all the time. I was a little shocked but maybe it's normal among boys?

he is my first boyfriend, and I don't have any brothers.. so I don't know if it's something normal or not?
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+1 y
and when I do him blowjob I feel kinda grossed out because of this ..
My boyfriend doesn't change his boxers often, is this normal?
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