Is it normal that my husband like to have sex with my mother ..

im a married women age 32,i have two beautifull daughters, my husband is a very good person but coming to sexual feelings , he is bit weird, he told that he WANT TO HAVE SEX with my mom, and if i ask why he got such feeling, there he told he is just wanted to enjoy , my doubt is if he is just wanted to enjoy the other body for sex, then why only my mom , there are many other women around , but why he is not attracted to them , he is so crazy to have sex with my mom in that way that he feels helpless himself. no matter he trying to avoid that feeling but still it has become a big problem in my married life , i dont know how to handle it , is this type of feeling is normal for men? i dont know how to handle this , he shares everything with me , but sometimes i feel sharing is also a problem to handle . i tired to keep hi always happy but still...