Sometimes people, both men and women, come on here and you can tell they're getting dragged along for a ride they didn't really want to go on and they don't know how to stop it.
...which, learning to communicate and set boundaries is part of marriage, whether it's about divvying up yard work or having a threesome with your wife's sister.
I think it was totally reasonable for Jane to ask. Her reply that there is no "normal" is the same thing I was going to post, because everybody has their own checklist of kinks and insecurities to address. Sometimes things happen and you genuinely wonder, "why does THAT turn me on", it's you and won't always be for everybody else.
You just seem like you're in a little bit of distress and got upset when Jane pressed the issue, which really makes it sound like she hit too close to home. It's hard for us to tell if you're getting off on what sounds like cuckold play or resenting it.
To be more specific about your question, if it helps you, we have two couples that we play with fairly often.
One are old friends of hers who she had fallen out of touch with. The wife invited us when she figured out we were toying with it. They trust each other and we keep communication between the same genders - usually the two of them find out we have a good opportunity to meet, then I and the other husband talk and figure out logistics. The other is a couple we met through them and she and the wife became good friends, as well. They text a lot, and get physical when we play. Again, she doesn't call or message the husband separately, and we think that's the best way to avoid jeopardizing those friendships or anybody saying anything stupid. Neither live near us.
Since we started, we've had a situation pop up where we are spending some time apart. We know ourselves well enough to realize it might be difficult, so we had some honest conversations. Some things are inconsequential, can be done separately, and don't need to be discussed in advance. Intercourse does. Seeing someone a second time does. We can both say "no". No sleepovers, no intercourse without a condom, nothing within 100 miles of the house, and nobody who is in touch with people we know professionally or socially.
This could all be summed up "we're both horny, physical people who like to go out and have fun, let's not get mad if somebody cums, but keep it away from our vanilla life".
We have no male friends we would play with locally. It would be a terrible idea that could really destabilize our lives if somebody went popping off their mouth about it. The situation that you're describing would really go downhill fast for us, and she wouldn't do it in the first place because it'd really be at odds with the way she wants to be seen.