Not the bad guy

Tried to call a couple of people, but that did not work out, so I am venting here.
We have plans on Saturday. They have been on the calendar for MONTHS! We have a costume/potluck/birthday party, and we are supposed to be there at 6pm. It is Thursday, btw.
[Husband] gets a text asking if we can feed the missionaries. He texts me, 'are we doing anything on Saturday?'
I tell him, yes, we have the bday party. (He hasn't said anything about missionaries to me yet, so I am just assuming he has forgotten plans again)
We proceed to go back and forth in text, until I call to try to clarify. We both get frustrated and he ends up yelling and hanging up on me...
Last communication is, 'we should never be too busy to feed the missionaries'. *stab stab, lemon juice.

So I am the bad guy for sticking to the plans and trying to get two costumes together, as well as prep a veggie tray, as well as take the car in (been without air conditioner fan for almost 2 weeks!) I don't think so. Not fair. We have to schedule and choose and as nice as it would be to feed the missionaries, we have plans! I shouldn't be made to feel like a jerk who isn't 'in tune' for this. I just want to go to my friend's party and have a good time.