>

Yes, it's your guest too. Don't be an asshole. Your partner is allowed to invite people to your gatherings too.
They asked for an invitation and it was given. They were told to come. If you did not want them there you should not have invited them. >

To be clear, they asked my partner. I was not involved in the asking process. This was supposed to be small, low key, because I still have a lot of work responsibilities. If they were just going to be at the party, cool, no problem. But they're at my house. Multiple days. They're staying here. That's a little more than a one-off. >

Sounds like you are mad at your partner for doing this without discussing it with you first. But those visitors did absolutely nothing wrong. >

I agree with your header, but then when I start to read your post you just sound like an asshole.
So let me get this straight, you agreed to invite this person to your party and then got mad when you actually had to be a host to them?
It sounds like the correct thing to do in the situation is to not invite this person in the first place, like what the fuck lol.
This person did not invite themselves anywhere, you quite literally admit to inviting them like??? >

OP did not invite them. OP S/O invited them. It seems like OP  S/O was talking "Oh I'm hosting a holiday party" and O/P friend was "that's great, I haven't seen you in a while, do you mind if I come".  OP is not a butthole, she just seems very stressed. If her partner refuses to help her with the grocery shopping or take some of the load off her then  that's a convo about their relationship. >

This is not the guests fault. They asked for and received an invitation. This is 100% on your partner. You should have said unless you are doing this, and this, you need to uninvite them. I cannot handle this extra responsibility. I will not. Do not treat these guests differently or poorly because your partner hoisted extra duties on you. That makes you a jerk. You want to take it out on your partner that's valid, but not on guests who were invited. That's not okay, and makes you a terrible hostess and jerk. You are arguing with people that you should continue treating the guests badly, you shouldn't apologize? It's too late, and if you don't make it clear to the right person ~this will happen again in the future, and it will be as much your fault as your partners~, if not moreso on you. Stop blaming people who were extended invitations. They deserve as much respect as everyone else. Jeez. >

Hence why it's in the unpopular opinion section. I'm being held responsible for someone else's agreement because we live in the same house. 
I have been polite to the guests. Doesn't mean that I think I should be bound by someone else deciding that having guests is a good idea. By your argument, once one person invites someone over, the other person living there is also responsible to host them regardless of inconvenience. You're arguing that people can't have boundaries. Because my partner said yes, I now have to rearrange my life regardless of what I had going on or I'm a jerk.