My hoarder in-laws are moving in to our new house. How to deal with that?

i dealt with your EXACT situation. What you need to do is this. Tell the mother, there is ONE condition to live with you. NO HOARDING THROUGHOUT THE HOUSE. Tell her, as soon as her clutter leaves her living quarters, YOU WILL THROW IT IN THE TRASH. enforce this rule with no exceptions. I also must warn you, that this is going to put a huge strain on your marriage. Especially since your husband seems to make important life decisions without consulting with you. You also need to have a pact with your husband, before they move in with you, that in the future, he backs YOU up 100 percent. Because any time a mans mother comes to live with you, she will put a strain on your marriage, As i said earlier. Anyway.. You need to firmly establish the ground rules at the start. Dont be shy about it, it MUST be done, or you will end up with a health hazard in your home, and a marriage in shambles. You MUST remain firm with your rules. It is YOUR HOUSE. if you ever ever need to talk to someone whos been thru this, (thank god shes moved out now) email me. monkeybearstripe@yahoo.com. Good luck, it wont be easy. The best advice i have 4 you is keep the house very clean, dont allow her to have her mess all over. She can decide, to not have her stuff at your house, or live elsewhere.