Oh, I absolutely agree that boundaries are needed.

But my feeling is that if you are secure in your relationship and set boundaries...there's a middle ground. And the best place within it is going to be different for different couples. As long as you aren't reaching the point of toxic jealousy/abuse, then set your own boundaries.

I mean, people have open relationships and make it work, and that's a very different realm of boundary setting.

And if you are sharing things with others you don't feel comfortable sharing with your partner, that's not about the friendship, it's about the marriage, if that makes any sense? The key is not feeling comfortable sharing things with your partner. If you don't, then something is wrong.