Hi. Well, your ex sounds dangerous and I'd take that seriously. I'd go ahead and stop showering with your boy because of that. I know at 5 I would stand outside the shower and help with shampooing and rinsing by reaching in so you could do that if you feel he needs help. It just isn't worth your ex causing a major issue for you.
I will tell you that when we go to the gym, my husband showers with both my boys . . . along with whomever else is showering as in the men's locker room there is only one big shower (glad I'm female).
Anyway, I am sure there is a convenience factor in showering with your son but it isn't worth the hastle of her accusations. good luck
There is nothing wrong with having a shower or bath with your 5-year-old if you know you're not doing it for prurient reasons, but there is a problem with doing it if you know your ex-wife is gunning for you and wants any pretext she can find to get you into trouble. To keep from having to go to court with your ex, it is no sacrifice to stop taking a bath or shower with your son.