Husband taking ED meds and didn't tell me

So how common is this?
Let me preface by saying I take no issue that he is using this medication...whatever he feels he needs to do is ok by me.
My issue is that he didn't tell me about it. I found a few stray pills that fell on the floor. He says he was embarrassed to say anything to me about it. We have been married for 25 years, we've been through a lot together. I feel this is something I should have been brought into the loop on. Again, no judgement from me, just a simple, " Hey, Ima try this out, see if it helps". There have only been a handful of times where he had a slight difficulty keeping his erection. And each time drugs or booze was involved, and each time he was able to get it back.
He says I'm over reacting by feeling disappointed in him for not telling me. Unfortunately, it's not the first thing he felt I didn't need to know about, so now I'm waiting for the other shoe to drop.
Am I making more of this than I should. Need some objective observations.

I am not sure that I can be impartial, since my own partner has several times done stuff behind my back (like joining a dating website for one). He went and got Viagra when he felt that he was not proving himself in bed, and felt uncomfortable about it. He and I are in a poor relationship, and my feeling is that this is why he is suffering from ED, not any medical reason.He told me about the Viagra purchase some time after purchase. However since he feels that he is no longer having sexual difficulties he is happier and therefore our relationship is better.
I cannot say if you should be concerned as I do not know the quality of your relationship. All I know is that there really is a lot my partner is hiding from me, and, really, why did he have to take a dangerous med when he knows that I am no longer worried about having sex, unless it is so that he will be able to prove himself to some woman he meets via the Internet

I didn't told my ex-girlfriend that I had Viagra prescribed, and I needed it because the side effects of my antidepressant or anti-psychotic made me almost impotent. I was embarrassed over that...