=)
Well Either he is full of sexual electric or he has seen 1 too many porn’s and think all women like fingers in there arse. (Unfortunately most do not)
Doggy style is not a sign of homosexuality. It has actually been around since the periods of ancient Romans and Indians. It was often referred to in the Kama Sutra studies.
Your best bet is to communicate with your husband and tell him you’re a 50's nun and like it missionary only. (j.k)
But tell him how you feel and Explore different options and interests. A relation is a two way street you have to give and take.
You might get the sanctity of your arse back and you may be willing to explore a different area.
There are a billion and 1 fettishes out there.