Help me - help my husband

First welcome to the forum. Since your room is pretty small I would just mount it on the wall nearest to where your projector will be mounted. 10 feet is about the minimum you would need back from your screen so I wouldn't go with too big a screen size or you may have problems setting up your PJ.

Also a square room is the worst situation..acoustically speaking..:thumbsdown:

10'x10' is a small space to work with. As mentioned above the square dimensions will be very hard to work with acoustically.
With that distance from the screen you would have to mount the projector right at the rear of the room and that would not give you much larger than about a 92" diagonal screen (too large for that space).
You will need to leave space for the front speakers on either side of the screen and 2' of space between the side wall and the speakers. Your seating will need to be placed about 3ft out from the rear wall so that the rear speakers can be placed and heard properly.

just like the above people said..10' by 10' is simply too small for a decent HT Sowie

If you are stuck with those dimensions, put the outlet for the projector as far back as you can. You will also need to be very careful in selecting a projector and screen size. With that short of a throw distance, you will be limited to only the smaller screen sizes with many projectors. Projector Central (www.projectorcentral.com) has a good calculator program that lets you play with distance, lighting, and screen sizes for different models of projector to see what works.

Also, check the projector manuals -- there is usually a table of throw distance and screen sizes that it will support.

But if you can buy even an extra foot or two, that would make your life easier for both the projector and the acoustics.