Maybe I'm crazy, judgmental, or atrocious (possibly all three)--but I think baby showers for more than your first child are over the top. This is a different situation because it's the husband's first child, but not so much. I believe in sprinkles for a child of different gender or babies born far apart, generally as a happy surprise, rather than a planned event.
That said, I do attend many of these events--for family only and only for the sake of keeping the peace. I'm sure not everyone has in-laws like mine (at least I pray you don't) but I do believe the majority of these events to be gift grabs or a way of soliciting gifts instead of simply supplying the needed items yourself. I've kept my feelings to myself, but after receiving a fourth shower invitation in as many years for the same sister-in-law, I do think it's ridiculous and entitled.
I don't understand, nor will I ever, why showers are necessary, especially multiple showers for the same couple. A baby does not need a shower to be celebrated, loved, cared for, or welcomed to the world. Most people are aware that a birth is a gift-giving occasion and will proceed accordingly. Why parties are needed for each birth, as if that birth is not special, unique, or sanctified unless a party is given, no matter by whom or the number of showers preceding/accompanying it, is beyond me.