He needs someplace he can go, work, leave it laying around, get up, go out the door and lock it.
I have a sewing room in our guest bedroom. I have to be able to leave stuff laying out, scissors, pattern pieces, pins, needles, etc...I have to be able to know that these items will not be messed with or played with when I am not in this room.
Your hubby needs to have that security also. Can you imagine the cost of a small child pulls an expensive computer off the table and breaks it into pieces? You'll have to completely replace that unit.
So I suggest you make room for him in either your bedroom or a space in your house where he can have absolute privacy and security.
I looked at rooms to rent in an old elementary school that currently houses a church. They have several businesses in the building too, birth right/choice (?) and some crafters have rented space too.
They wanted $150 for a larger room and just $80 for a small one. I could do fine with the smaller one but would really love how clean my house would be if I rented the larger one. All my scrapbooking stuff, sewing stuff, paints, brushes, craft books, wood crafts, ironing board, all the stuff that takes up our personal space every day. If I get this stuff out during the day I have to stop, clean up, and put it up before the kids get home from school every day.
I think you need to consider this. How much money does he make each month. He can have a successful business but if he is spending all his income on rent and utilities he's not successful at all.
Think about your home. Where can he find some personal private space that locks up? If you have 2 bedrooms and no extra room then it might be that you guys need to find a larger home with more bedrooms or a designated office space.