Am I in the wrong

No youre not wrong and youre not alone. I have very little sex drive since having my baby 15 months ago already

Maybe he was thinking about you and not other girls?

Having a low sex drive post childbirth is totally normal and make sure you don't feel pressured into sex more than you want to now that you know he does have a w**k.

But in my opinion, and I do know that everyone has different views on it, him having a w**k wouldn't bother me.

I did when I had my first child I was okay with him doing it as long as it wasn’t with other women. At least I knew he was home with me.

Im probably going to get some stick for this comment but here goes...
Masturbation is the most normalised thing to do...Just because you are struggling with your libido doesn't mean he is and you can't tell someone not to do something. He was having private shower time in which you wouldn't have known about. Maybe you need to have a conversation about the quality time you have together. Personally I would rather my husband Masturbate than seek attention outside the relationship.

He has needs though. If you as a partner can’t currently meet them (and yes we have seasons where we have no libido and can’t match his libido, that’s okay) then I’d rather him wank and get off that way than step out physically altogether or pressure you for it when you’re too tired/not on the mood etc. He may be thinking about you because we can’t prove that he’s wanking to other girls.

I don’t think he’s wrong. If you didn’t actually see him watching porn or looking at another girls pictures how do you know he wasn’t thinking about you? There has to be some kind of compromise.