I don't know if this is helpful because I think it's frowned upon, but my bf and I are in an open relationship while apart--with rules/boundaries. Full disclosure with each other (who we're going to hook up with, where, and when) and to our other partners (that we're only looking for casual sex bc we're already in a relationship), and the encounters are strictly sexual (no hanging out beyond meeting for sex). When we're together we only sleep with one another, though when we close the distance for good we'll most likely engage in threesomes from time to time.

It's sort of a "last resort" type of thing though, because we FaceTime constantly, send each other videos/pictures/snapchat WAY more than we hook up with other people. The sex outside our relationship is just a release. It's never as good as the sex we have together, so it can be disappointing and make us feel lonelier. We've started sending each other videos of us having sex with other people, which is a turn on for both of us.