Generally not, and not since we've been a diad/triad (boyfriend is a pretty new addition as a partner, though he's been a lover for both myself and husband for some time). The closest I get to jealous is probably if someone suggests my access to someone I care about is on their sufferance - though last that happened was like fifteen years ago.If it's not too personal to ask, do you ever feel jealous or uncomfortable with either of your partners other partners?
I've seen lovers have relationships that I didn't feel entirely at ease with, but that's been out of concern for them more than anything. Seeing someone I care about do something I suspect is going to end with them getting hurt isn't a nice feeling, and I would imagine most people feel the same about that.
I would be uncomfortable if one of my partners took as a lover someone I had an actively antagonistic relationship with. I do respect their right to make their own choices, however, so the most it would likely amount to would be "please let's not talk about that person". There's very few people I have anything close to that kind of relationship with, however, and I don't see my partners being attracted to any of them, so that's a purely hypothetical standpoint.