I agree with the others, twin beds and maybe a night stand between you. You would be in the same room but out of reach of any swinging arms. I also think that your husband needs to talk to his doctor, he could have something serious going on. My daughter used to sleep walk every night and was very combative. She would be screaming and swinging her body about. Every night I new she was going to go through this. I talked to her doctor and he could not explain why she was doing this. This went on for two years. Then because she was having allergies her doctor put her on an inhaler. The day she started the inhaler the sleepwalking stopped. It seems she wasn't get enough oxygen when she was sleeping. We have not had another problem with the sleepwalking. Maybe a sleep study for your husband would shed some light on problem.
I hope you find a solution for this, your husband sounds stressed about it and the stress may be making it worse.
I have been known to punch my hubby or kick him in a very sensitive area in my sleep. I take Trazodone, so I don't remember it at all. Usually on those nights, though, I vaguely remember dreaming about my ex.
You said that he used to have those dreams years ago...did something happen to him? It could be a psychological thing. Sometimes, our subconscious tries to work things out in our sleep. It comes alive, so to say. A sleep study might be a good thing, or possibly hypnosis by a licensed therapist or doctor.
As for right now, is there any way you can get an air mattress? Some of them aren't that expensive, and it would be better than your couch...just a suggestion. Good luck sweetie.