Strike! I've been having this issue (in my 3 year relationship) as well and thought a lot about it. Your approach to this matter seems to be liberating and I aswell approve of this! :)
Romantic relationships have only existed for such a short period in the history of mankind. The odds of having a monogamous relationship work out for all of your life are pretty low. Considering we're still humans driven by emotion. I'ts just our primal instincts messing it all up again and again...

Thanks for writing this piece of content!