Husband told my MIL it's ok to invite extended family to our baby shower without my approval

As the title says... want to get this off my chest.

Just some background. I'm 32 weeks, my husband and I are expecting our first child, a boy.

I was initially on the fence about having a baby shower at all, because I don't like being the center of attention due to my social anxiety. We ended up deciding to do one next month, a very low-ley, co-ed BBQ. No games, decorations, registry etc as it's just not what I want.

Made the event on Facebook and invited immediate family and our closest friends, which came to a total of around 20 people.

My husband tells me yesterday that his mom texted him and asked if it was okay to extend the invitation to aunts/uncles/cousins (my husband's extended family is HUGE) and he said yes without consulting me first.

I was immediately pissed. We don't see these family members very often, maybe once or twice a year and I don't know them that well. There are 20 of them, maybe more. So now the attendance for the baby shower has potentially doubled against my wishes.

Husband's excuse was "well we will get more things for the baby". That's not the priority for me with this. I want to have a nice day with the people closest to me, enjoy a BBQ and have fun...

Something I was looking forward to I'm now dreading and feeling so anxious about. Doesn't help I'm hormonal either. A part of me just wants to cancel the whole thing. So frustrating.