Hi Spin-man and welcome, though sorry you have to be here. during your prostatectomy not only is the prostate removed but also the internal and prostate sphincters, leaving only the external sphincter, which unfortunately is seldom used when you have all 3 sphincters, so loses it's muscle tone as you get older while at the same time your bladder walls thicken and get more muscular, so it's up to you to re-train the sphincter and unfortunately it can take some time "months". The best exercises being pelvic floor exercises there are lots of video's to show you how, though don't assume more is better aim for 5 x 10 seconds 6 times a day. Voiding when you get the urge to pee try to hold it in, you will need to be patient as results won't be instant.PS if you can do them in the bathroom it will give you more confidence to try for longer.  And Pilates, Not an obvious choice for us men i know but great for strengthening your lower abdomen, or inner core as they call it, best wishes.

Eddie