What Causes Difficulty To Attain Orgasm?

I am 67 years of age and still working and very active, but at times when my wife and I get amorous , there is a pleasant buildup but oftentimes, no ejaculation to speak of. I am on meds for hypothyroidism and for hypertension, but this last round of meds seems to be a lot more user friendly . One urologist I visited several years ago simply said, Hey, you re over 60. Your system is shutting down. That is not exactly what I wanted to hear! Where do we go from here