A number of companies offer wireless headphones, some based on Bluetooth A2DP, others based on proprietary RF schemes. A handful of headphones have built-in support for multichannel audio, but some receivers support "Dolby Headphone" or equivalent, which synthesizes surround sound on any headphones.

As to supporting *two* sets of headphones, you could go with a y-adapter and two base stations. I'm sure somebody must offer a single base-station solution. If you can find one, that would be interesting, for sure.

You could also buy yee olde headphone extension cable, a y-adapter, and so forth. With two of you plugged in, that sounds like a recipe for disaster.

One way to keep things under budget is to use pre-existing wired headphones that you might own with some kind of Bluetooth A2DP adapter. Several companies offer them. Dunno if any of them are any good or not.