I've been on T replacement for 20+ years. I am 53, reasonably fit and generally very interested in sex. I do have my health issues and it's not uncommon for me to simply be exhausted at the end of the day, and crash. Even so, given proper timing (not waiting until 11PM when I'm so tired I can't see straight, for example) , sex could be a regular thing "if" ..... let's just say 2 willing (and affectionate) persons are required.
Menopause. It's an issue for the man in a typical aging relationship. I certainly did not know what to expect. More specifically, I did not understand that 2 out of 3 women completely and totally lose interest (starting around age 45-47) in sex and affection. Coupled with the fact that women physically change, dry out, and become internally fragile. Many can't have sex, post menopause. Unless modern medical science helps out.
I found myself in my early 40's, as horny as a 20 year old, with a unwilling and physically incapable partner. Not just for a short period of time, but for years. Folks, that's TOO SOON.
Yes, proper HRT works wonders for some women, and many report feeling younger with it's use. But HRT does not fully restore all (or even most) women to their former, younger, affectionate, "horny" selves, and, IMHO, at best, can be said to make sex possible, by increasing vaginal wall strength and lubrication.
I truly believe that many of the men here are not young, and with proper T replacement, will find themselves with a strong libido. Those of us who are faithfully married may also find great frustration. It's worth noting that T replacement affects a marriage/relationship, and it's worth considering all of the information carefully. From my end, I felt unwanted and used. I provide, work long hours, extra days, and receive no reward what so ever.
We can kid ourselves into thinking that most or even many, post menopausal women are still as affectionate and have a strong libido. Or we can accept the reality that most post menopausal women do not retain these aspects of personality or capability. And understand that T replacement (and Viagra etc) can cause unforseen issues with the man and his view of the relationship.
One can search for menopause and sex. Most of the "facts" have been watered down. Reality is rather harsh, 2 out of 3 lose drive, interest and ability. https://www.menopause.org/for-women/sexual-health-menopause-online/sexual-problems-at-midlife/decreased-desire