I don't know if this will help you, but it may be helpful information for your wife to understand your sexuality.
My wife of ten years struggles to reach orgasm. I'm talking upward of two hours of foreplay to get her there. I am not exaggerating. Most of the time she just doesn't feel it's worth the effort.
When we first got married, I was like your wife, I felt like it was my duty to help my wife orgasm. I really felt like a failure when it became evident that most of the time I either couldn't get her there or she didn't even want to try.
I actually never got over that feeling of failure until I began HRT and experienced a sex life where I didn't have an overriding drive for orgasm. Unlike you, I can orgasm with some effort (maybe 10 minutes or so of continuous stimulation), but most of the time I really don't care if I do or don't.
It sounds really cliche, but this is a situation where communication and listening will probably prove important. Somehow she needs to understand that your sexual experience, reactions, and needs are changing and it's not a bad thing.
I was really fortunate in that I married a woman who hates vaginal penetration. I tried for years to avoid it and made a lot of excuses but she always thought it was a little weird that I didn't like doing the normal "guy" things in bed. She learned to enjoy my lack of enthusiasm for penetrative sex, since she hated it. After I came out and later went on HRT, when my sex drive changed, I told her I never wanted to engage in penetrative sex again. She counted it as a great relief and she is content, as am I.
We do have the new issue of me not being interested in sexual activity. It crosses my mind occasionally, but I never feel like pursuing it. My wife is trying to get me to engage in some physical intimacy, like hugging, cuddling, etc. I find it awkward, but sometimes I kind of enjoy it.