For us, we started out swinging. It is extremely difficult finding couples where we found both attractive, so that didn’t last long. With time, we learned that swinging wasn’t really for us anyway, but maybe we just haven’t found the right couple.? We eventually opened up our marriage to where we both are able to find singles on our own…and technically couples if we wanted. We can have threesomes or just play completely alone. We don’t really have many rules besides condoms are a must and no anal. We also tell each other about anyone new that we feel like it’ll actually go somewhere. We both also have each other’s phone passwords and can technically go through each-others phone, but that isn’t ever necessary since we just communicate about everything…but it’s there. I wouldn’t know any boundaries that we would add besides the two mentioned. As long as our relationship and home is being taken care of, we kinda just do what we want.