Chakka, my response is going to be derived from my own personal experiences that loosely mirrors yours. I may be way off base but maybe my input might might be of some benefit.
Is it possible that you've oversimplified your reasons for jealousy? You say you feel it's because you started off playing together and then started playing more seperately and you thought that might be the reason for jealousy. I think it's possible that it runs deeper than that. I went from being a non-jealous person to a jealous person for different reasons than you. What I realized is when I analyzed why I was feeling the way I was that I would find more simple reasons in the beginning but as time progressed and I had the simple issues fixed it still didn't fix the problem. It ended up running deep and took me years to really find the source and fix them.
Often when a person has had problems with feeling jealous in the past they start to feel more guarded of their feelings, they want to prevent it from happening. Those guarded feelings often make a person begin controlling situations they didn't used to control to protect their feelings. When a person goes into a social situation guarded they are no longer go with the flow and the night can deteriorate with simple things setting them off. A person who's feeling guarded (including myself) may go out thinking: I'm so excited to go out, I really want us to both be happy, I hope we've set the right rules to prevent any ill feelings from surfacing, I hope my husband doesn't do anything to make me feel bad, Oh I hope I can relax and just have fun.... Then one simple thing can set all those feelings into a downward spiral and then all feel a person can do is dissect the evening to figure what went wrong so it doesn't happen again.
Does it really matter what that one simple thing was? Maybe your husband didn't communicate properly with you, maybe he didn't make the best choice, maybe you didn't listen, maybe you should have joined, maybe there should have been less drinking, maybe... who knows... I think if it wasn't one thing it was going to be another. What really matters is did you go into that situation feeling guarded and if so why were you feeling that way and that's more the issue to fix.
I think you're not in the right mind frame yet for swinging. I think you need to dig deeper for what really makes you jealous (more than just being in seperate rooms) so you can let your guard down. I think it's time for a real break and some real soul searching. Don't put yourself into those situations until your really ready. Once you can let go of these issues I think you'll be able to return and enjoying swinging again, just like you used to.