They vary greatly from pretty disgusting to pretty clean. There is a website you can find using Google that has reviews of theaters.
Some will be very couple friendly others are not. Same with the crowd. Some might be too pushy for your liking.
The set ups also vary,. Some are a series of small theaters others a quite large. Some include booth areas (glory holes) some don't.
Seen some that have couches for seating. Some that have a table up front for...well you can guess.
My suggestions are:
1). Research the place first.
2). Maybe have the hubby visit first to scout it out.
3). If they have a store attached, visit that first and gather info. Talk to the employees about bringing your wife there.
4). Bring towels to sit on. Wet wipes for any needed clean up.
5). If you want to play even if just with each other, think easy access clothing.
6). Be aware of surroundings and others, if anyone ignores your indications to back off immediately leave and alert the desk clerk. Never heard of anyone getting assaulted but some that have had creeps ruin the fun.
7). Condoms
8). Many places have couples areas or nights. Think about going then. It won't prevent you from finding non couples to play with just generally a friendlier environment
Great fun can be had at them, but some care should be given where and when you go.
Sadly non left near us, used to have some fun