Your issue of having trouble with climaxing would be caused by low Testosterone- I’ve been on monthly T treatment along with my wife for many years and we are still enjoying sex into late 70’s.. I would highly recommend getting check .
Glad to know you haven’t given up on sex at 74 - I’m 69 & no plans to give it up anytime soon!
Now a Q: Does this ED occur when having partnered sex? If you are able to get good erections by yourself, that’s a sign there’s not a physical prblm. If it’s only occurring during partner sex, it could be just ‘performance anxiety’. Obviously, at 74, you may not have a willing partner, so it’s understandable to take care of your needs on your own.
Of course, as men get older, our sexual responses often start to decline. ED meds like Viagra, Cialis, Levitra, etc. can help, so ask your Dr about getting treatment with one of those. Your Dr will want to check you out for other health issues that can translate to ED issues - high blood pressure, diabetes, cardiac issues, etc.
The good news is, you at least CAN get erections, so the issue is maintaining them & that's where ED meds can help. You can also try some natural treatments that help w/ blood flow - L-Arginine & L-Citrulline can dilate arteries & aid blood flow to the genitals. Maca root & Epimedium (so-called ‘Horny Goat Weed’) can help.
Of course, there’s also the issue of low testosterone, a common problem for older guys, so your Dr may want to check your T-levels in case that’s a factor as well...
One thing that you definitely SHOULD do in any case - continue to stimulate yourself at least several times a week to promote blood flow to the penis - lack of frequent erections can cause tissue changes that will ultimately make satisfactory erections even more difficult to obtain...
Good luck & let us know how things are going...