I have to ask- are you really horny & needing it each time, or are you doing it to see how many times you can do it? Because my wife and I (both mid-40’s) are still frequently interested (4-5 times a week, not counting solo work;)) but other than the occasional 2x/day (just after waking & just before bed), neither of us are usually interested in it more than that. We’ve taken long weekends away without the kids and hit 3x/day, but the genuine interest in having sex more frequently than that would wear off pretty quickly.
We were definitely horny and needing it - this wasn’t out of our interest in furthering the science of adult sexuality.
I think the fact that we only see each other about once a week has a lot to do with it. We regularly have sex 4-5 times each visit, which I’m sure would not be the case if we were living together or seeing each other more often.