It's normal for 8 years relationship.
You can't expect he will have sex frequently with u like beginning when u said u already did ur part. U have to do more than that to keep sexercise excitement such as role play, wearing uniforms and etc.

I always surf at a Taiwan forum where they will share the pictures of their partner's sexy parts, cause they will feel exciting when the comments are about saying how envy or lucky to have such a great body gf etc.

It's like the things when more peoples want it will make you baby it more.

Some even going further till having threesome.

You can try to make him jealous like talking with another guy in front of him, praise random guy in front of him etc, the jealousy will make him wants to "conquer" you.