Here is something I do take seriously: We have our "couple" friends and that is healthy, fun and necessary for us. BUT, I think it is soooo important that we also have "non-couple" friends. I have women with whom I enjoy things outside of a doubledate situation. As does he.
Having interests and friends outside the relationship is good for us. Not sure if it is good for everyone, but it is imperitive for us. I also take vacations with my girlfriends on a regular basis.
We've talked about how important it is for both of us and I'm very happy about that.