It had tapered off for sure after 20 years. But we have recently gone through a period of revelation after kids and a somewhat dead bedroom situation. I sat her down and had an honest discussion about our sex lives in general and the result was phenomenal, way better than I expected. After this very honest talk we discussed our needs in depth. She is not the type to really want sex, but when offered it was more than up for it (this is called reactive libido - where she won't seek it but when presented is ready to rock and roll) - in short she will rarely initiate. This was hard for me, it is hard to be the one to initiate 100% of the time, until I understood the psychology behind it - she is a really shy person.
Part of this discussion was about blowjobs. I love them and at that moment they were whatever to her. Then we discussed what we liked about giving each other for sex, and my answer was simple. I don't have sex for myself I have it for her, and I eat her pussy every time, not that I expect a BJ, but that I really love doing it for her (and she enjoys it). Something clicked and she finally understood that sucking my dick wasn't for me it was something for her to give me. She mentioned her hang ups with the connotation of sucking dick, how guys talk about it in a degrading way, and she realized that with her husband this was not the nature of the act.
In short, I have had more blowjobs in the last six months than the last 20 years. She also self realized (surprise to me) that to really fulfill the tasks she would start finishing them. This is literally something she tried twice, once in high school and puked and another time for my birthday years ago with a comical ending. She got to it, nailed it, and has been going strong ever since. It was all in her fucking head, and she never equated blowing me with bringing me joy and loving that until now. Sounds sad, but I totally respect where she was with it as a woman (I get the negative connotations given to it) and honestly could not be happier with the outcome.
The end result is, if you are having issues in your relationship, and it is still a good relationship (she really is my best friend to this day), then just talk it out and be fucking honest.