I'm going to go out on a limb and take this as a serious conversation, why not.
I think varying libido is normal, for both men and women. I think women, especially if they didn't have much experience before marriage, experience a let-down of sorts that it isn't for them what they thought it would be, and what they observe it is for the guy, and that can cause a real difference in libido levels in the couple. It is also normal for levels of hormones to wax and wane over the years, due to many factors, such as age, weight and general health, specific illness, relationship status and issue within relationships, medication (both recreational and prescribed), daily stress, stressful events, etc.
I experienced pronounced libido reduction during my major illnesses, especially during chemo and while on pain-control regimens. I do not feel it is drastically reduced as a baseline from my 20's, however, even now in my 40's. Hard to get a baseline on the mrs. as she spent so much time pregnant or breastfeeding or on birth control in between during the early years of our marriage that she didn't even have a regular period until we had been married nearly 12 years. But to not be in sync with one's significant other I think is pretty normal. For maybe 1-2 weeks of the month we are in sync, and that is the sweet spot when it's always great, for another week to a week and a half, mine is stronger than hers, and for maybe a handful of days it is the other way around. We both recognize and accept this and try to be accommodating when it is "their turn" so to speak, but we also respect the low times for each other and give each other some space as needed.
I think all that is normal in a healthy relationship, and just part of life in general.
