Please help!! My boyfriend LOVES to eat me out but spits and cleans his mouth right after???

My boyfriend says he loves how i taste, and he loves to eat me out he will do it as long as i want and he genuinely enjoys himself. My question is,

As soon as im done cumming, why does he run to the bathroom sink to rinse his mouth and even spit out water??? Instead of just going right to the fucking part??? Do i taste nasty even tho he said i taste great?? :/ its making me feel a tad insecure.