I'm new to the game and new to this site, so hopefully I'm ok in asking for help with a situation that is plaguing our otherwise happy group.
My roommate and I have been hosting D&D 5E in our basement for several months. I'm new to the game and really loving it. Recently, our first DM moved away and we had another player take their place. The issue is that he brings along his girlfriend who is a disinterested player and doesn't understand the game. He has made the entire story line center around her in an effort to win her attention. The other players and I just sat through a 5 hour session where we were practically extras in a bad soap opera/love triangle that had two "fade to black" moments between her and an NPC. The plot is going nowhere and we kind felt like we were watching some sort of bedroom role play. No sex-negative judgement here, but we all kind of wished they had saved that bit for when they got home.
The game before this one wasn't much better--the DM had to cut the game short because he had drank to much earlier and wasn't able to continue. To compound the issues, his girlfriend will fall asleep in the recliner near the end of the game unless something dramatic is going on with her character. To help with this, the DM suggested stopping the game earlier, which would be ok, if they weren't late to the game most of the time. The straw that is breaking the camel's back is that the DM cancelled at 10pm the night before gameday because the girlfriend didn't want to play--so apparently they aren't willing to come independently of one another. Am I alone in thinking that's a bit inconsiderate to our players, especially if you're the DM? We understand that stuff happens, but it was sort of lame to cancel last minute.
I know the answer would be to find another DM, which we have a seasoned player more than willing to fill that roll. But we host this out of our home, want to remain gracious hosts, and we generally like the couple outside of all of these gaming issues. (Except for one moment where the gf started talking about another player behind their back, so there's that gem.) On the other hand, they aren't being very considerate of the schedules of 5 other players in an established weekly group, and the game isn't very good as of now.
His plots move slower than DragonBallZ seasons, and the group wants another player, who is a seasoned AL GM, to step in for some faster/more reliable and on point gameplay. The player GM'd a one-off last weekend that was fantastic, and we want him to keep going.
Everyone in my group is super polite and are trying to be supportive. So on one hand they are trying to be patient, but they are voicing their concerns to my roommate and I, especially after this last-minute cancellation thing. I think they are looking to us to handle it since we are the hosts.
So I guess my question is: How should I go about fixing this? Has anyone been in a position where they've had to "fire" your DM? What did you do or do you have any advice or viewpoints that I may be overlooking?
TL/DR: How do you politely tell a DM that their services are no longer required?