If you think it is irrational, it won't be your thing. Only by living and experimenting will you ever know for sure. I have btdt with relationships and now find myself in a loving marriage where we are monogamous. I don't see that as irrational at all. I actually see it as a great growth experience for both of us. We are taking love to levels that you can really only experience by spending time together and going through "life" (good and bad) together. I love growing old with my husband.
But that's just me.
I say don't limit yourself to anything and certainly try not to let "labels" hold you back from experiencing all there is to experience (even if "the masses" also do it).
Follow your heart.