Finding other people open to this sort of thing

First post on reddit! Been lurking for awhile... Mainly just looking for some advice: My husband and I are very new to exploring the possibilities of having relationships with other people outside of our marriage. Prior to a few weeks ago, we had only ever had sex with each other, and are sort of looking at this as a way to satisfy our curiosity about being with other people. At this point I'd say what we're looking for is somewhere between polyamory and swinging - neither of us is into one-night stands or having sex with total strangers, but at the moment we're not really looking for either of us to have a full-on "boyfriend" or "girlfriend" - so really more of a friends with benefits situation. Anyway, my question is, how do you go about finding people who are open to this sort of thing? I sort of stumbled across a partner just by random luck - he was a fairly new friend of both of ours, chemistry developed between he and I, and my husband decided he was ok with the two of us having an fwb type of relationship. So now both my husband and I would really like the same thing for him (I'm definitely at least as excited about it as he is!) Nothing seems very likely with any of our current friends, and in the circles we hang out, we don't tend to meet a lot of new people very often. So that leaves...trying to meet girls at bars? Not really his thing, and seems like it would be really hit or miss trying to find someone open to this kind of relationship. Internet? Any specific website recommendations? We're still young (23/24), but now that we're out of college, it seems that much harder to meet people, and especially people open to a somewhat poly relationship! Any advice would be much appreciated! Thanks!