The heart will keep on loving anyway, long past the time when it is healthier to give up and move on.

I'm just saying that partnership should be regarded as a contract, and the bottom-line expectations spelled out--even written out and signed--in advance, and kept in a safe place. Not just covering the dealbreakers, but contingencies like what to do if one of you ever changes your mind about nonmonogamy, falls in love with someone else, starts earning much more money than the other, or just gets bored with the arrangement.

As a lifelong (and now old) romantic, I've learned the heart refuses to grow up, so head must look out for the interests of both.