I live in a house in a resort area. This house was bought with the intentions of using it as a vacation place and is deeded to the male members of my FIL's side of the family (that_one_hubby, FIL, BIL, etc). However, that_one_hubby and I were stationed overseas or in other states until 2 yrs ago, and most of the others rarely visit the resort area, so BIL and his family are used to being the only family actually using the house. that_one_hubby and I moved out here after his term of service expired to live full-time. We agreed to pay half the mortgage on the house, while BIL pays the other half. About 3 monthes ago, that_one_hubby moved to a big city about 3 hrs away since there was a school he wanted to attend there, so currently it is me, that_one_dog, and that_one_puppy living in the "vacation" home. Upon becoming full-time residents of the house, that_one_hubby and I invested a large amount of money in the house for renovations, etc.
BIL has been disrespectful of our space/property since we moved in. I have told him multiple times that I find it offensive for him to comment on the organization, location of furniture, etc., in our bedroom. I have made him well aware of the fact that that_one_hubby is the only person whose input I need on what goes on in our bedroom. I have been diligent in keeping the common areas of the house (kitchen, family room, laundry room, game room, etc) clean, organized, and ready to be used by my in-laws.
I received a text from BIL the other day stating that he needs me to have my bedroom 100% clean because he wants to have a big party for his son's birthday this weekend and that_one_hubby received a call from FIL stating that BIL will "probably" want to use my bathroom. I responded to BIL via e-mail, stating that there is no reason for him, his family, or his guests to need to be in my room or to walk all the way through my room to use my bathroom. (The house has one functional bathroom in the common hallway, one bathroom that is accessed through my bedroom, and one that is not currently functional because it is still being renovated.) BIL responded telling me that I need to comply with his rules, and let them use my space. In the past, I have allowed the use of my bathroom on a case by case basis (i.e. If I am sitting at the kitchen table and one of their guests comes in and notices that the common area bathroom is in use, I have directed said guest to use my bathroom). This will probably not be possible this time, however, since I am having a major flare up of my chronic pain/fatigue this week, which I explained to BIL. I would also be wary of letting children in my room, since I recently started taking some prescription medications which could be dangerous if taken by a child. This whole situation is kind of amusing to me, because that_one_hubby and I have attended outdoor parties at BIL's home where he has rented portajohns and expressly forbidden anyone from going into his home to use the facilities. I have recommended that BIL rent a portajohn this time or restrict the number of guests he invites to a number that can be reasonably accommodated by the one functional bathroom in the common areas.
I also explained to BIL that I understand he is used to having the run of the whole place, since his family used it the most in the past. However, that situation changed when that_one_hubby and I became full-time residents in the house. It's ironic because this whole entitled attitude of BIL's is something that I would be appropriate (or at least not completely offensive) in almost any other situation.
I am so desperately trying to have a polite spine here, but it is so difficult!!! I am greatly offended that BIL thinks he can just demand access to my sleeping quarters. Could I say something else to be more effective yet remain polite?