I need help.... Advice

My husband kept on insisting to explore more into.sex and been asking me for a threesome with another chick... He knows I am not into this and I am seriously never going to do it.... I am very lost and very hurt at the same time. He told me I am being very selfish and only.thinking about myself... I am very open to learn more and give him pleasure but not with a third party. I am not a religious person but this just hurt me alot.. It makes me feel like I am not enough for him.... 😭😭😭😭😢😢😢😢😢 Help....