While I certainly applaud your care and caution, that's, um, pretty restrictive. Put yourself in the shoes of the other couple. What do they get out of this? They get to watch you...not cum. Oh, and a little touching. That's nice and all, but I don't think very many swinging couples are going to see this as a hot nite out.
Obviously, you're very concerned with each other's comfort zones. Do you know what, specifically, each partner has reservations about? Examples include "if I see him with another woman I'll think he's dirty", ""what if she cums harder for him than she ever does for me?", etc. All normal and natural and all swingers go through this.
If you can get those issues right out front, perhaps you can devise specific ways to deal with them. Maybe if you talk them out first, you'll find they aren't really such big issues as you fear? That's a pretty common experience.
Other couples don't need a guarantee that you'll party. Anyone can say no at any time. But if there isn't at least the possibility of *some* sort of orgasmic something-or-other, well, it's not really swinging, is it?
Why not remain open to the possibilities? You can say no or stop at any time. My suggestion: try and figure out, between you, what your "ideal" first-time might look like. MFM? FMF? Couple? (threesomes are "easier" for beginners imo) Soft or full swap? Then look for experienced folks interested in the same sort of thing. Try it and see. There's no other way to find out, really.
To be crude but perhaps wise for a moment, when it comes to pussy, you can't break it, and you can't wear it out; we've tried.
And remember who you're going to spend the rest of your life with. You're loved and safe.
With those things in mind, get
Mr. DBStPete