Do YOU want to be with him?
That is what important.
Yes we lose interest after so many years, some claims they don't but it is rare.
You had lost him sexually somewhere. He is not happy with his sex life with you but he is wanting to keep his comfort.
He is also aware of the fact that if you 2 divorced you will take him for all his worth and he will pay you pretty penny for a long time.
It will continue until he will fall in love with his next flame. So far he is just fulfilling his sexual void. You can be the one to change your way. Ask him what is that he gets out of other women that he can't get from you?
Passion? Very well could be. Do you still atracted to him sexually?