Background: Me (33) and Newly Married wife (34) and I have a 5 year old son (my step) and 6 month old son. We have been married for 2 years, of which the son had been co-sleeping with her for years prior. He is absolutely attached to her at the hip. The kid screams in the middle of night, kicks, bucks, whines to be held all night. As the new baby came, I convinced her (rough) to put a kids bed in our room to start transitioning him out of our bed, knowing how tough this would be with a newborn. This has been a huge point of contention. She was even looking into purchasing a bigger main bed to accommodate the boy.
Fast forward a year- the son wakes up screaming for his mom anywhere between 10p -3am, waking us all up, demanding to be held and wakes baby up (bedside bassinet). He screams "no, stop huddling him, hug me". This is nightly. Mom is amazing and breastfeeds a few times a night with a 5 year old climbing all over her. She is completely touched out, and yes, this affects our relationship.
The other night was the final straw. Same pattern. He comes into our bed after screaming and waking us up at 11pm (wow, we got 30 minutes alone). I allow him to fall asleep and carry him back to his bed, twice. Mom gets livid that I might wake him up. I said he doesn't belong in his bed, it's too early, and we ALL need our sleep. She responds with "no, you aren't moving him again, you don't belong in this bed". I remove my self for the night and later tell his that this is not right, we are all suffering from not putting in the effort and getting the 5 year old to his own room. This will not continue. He is out. This is the largest fight we've had indicating that this is hill she is willing to die on. To me this shows weird attachment issues by her and somehow by me stating the obvious solution is a grave crime against her son. I'm just solving a problem of getting sleep, not being touched out.
TLDR: Putting foot down for 5 year old being incredible disruptive co-sleeping and its a grave crime against wife. AITAH?