10+ years to figure it out

I (M35) have been with my partner for over 10 years. First years the sex felt perfect. We had a kind of routine where she would ride on me first to orgasm, and then I'd have my way with her.

She never liked foreplay, oral, or anything other than "regular sex". While I've always had quite a lot of fetishes (to the point where I can't really think of much I wouldn't be open to trying). But at the time, I was completely fine with the situation.

But after a while things got pretty stale. We started having sex less. And even when we did it, it felt boring and mechanical. At some point we only had sex every 6 months or so. She would sometimes try to initiate, but I would rather save my load to masturbate to porn a bit later. Of course there was some guilt, and a feeling that this wasn't normal, or how it's supposed to be.

But we do love eachother a lot. I have a mild case of autism, and it's not easy for me to have anything normal in my life. I was content with what I had.

However, we're both not getting any younger. She always wanted kids, and we've come to the point where I need to commit. And it feels so hard to commit to a life without passion. Even though day-to-day I feel content in this life.

On the other hand, I also can't justify breaking up a 10+ year relationship with someone who cares for me, who understands if I get stuck in my head etc... over "just sex" ? In a way I feel I've won the lottery with her, but at the same time... the thought of never again in my life getting f.e. a BJ feels horrible.