Sounds like you need couples counseling. Pretty much none of that is good. Nobody's parents need to be deeply involved in their marriage issues, especially if one partner is going to weaponize the other partner's parents against them.

My daughter’s marriage broke down, in part because he would often bring his parents into their fights. Once he tried to see if I would give an opinion about a disagreement they were having and I firmly told him that I had absolutely NO SAY in any of their arguments. He seemed a bit startled by that. The two of you need to set some “argument boundaries”. No bringing other people into the fight, no bringing up argument points that have nothing to do with the topic, etc.

from now on, if it's on the floor it's in the trash. If he wants to be a toddler, treat him like one. and your mother is fair game for absolutely losing your shit on and putting in a time out

I'd start working on my exit plan, sweets. He sounds like a raging **** gobbler and your 'mother' is clearly a ****. Decide whether you want to put up with this for the next 20 years or the maybe 2 it would take you to organise a new life somewhere sunny. Well, as sunny as this bloody island gets, anyway.

Have you ever tried shoes? They're great.