while dating and in marriages. What often happens is that boundaries are not established before problems occur. So, when they're hit in the face with them, they're handled poorly (e.g., swept under the rug, overblown, etc) and people feel obligated to "work it out" or abruptly leave without trying to work through it.

I think people are too afraid to discuss deal breakers cause they fear it might come to fruition and they'll grow old alone.