My Theory About Relationships and the Sunk Cost Fallacy

This is how we think things go:

We make perfectly logical, rational decisions based on the future value of your possessions, investments, relationships and experiences.

However, this is how things actually go:

We make decisions based on emotions and feelings, which are tainted by the investment - be it emotional or financial - that we accumulate, and the more we invest in something, the harder it is to let go.

This is something that's known pretty well in the financial world.

If you've invested a million into something, even when the price starts tanking, it can be extremely difficult for you to take your money out to save your ass, because you've invested of your money into it. In other words, the target of your investment becomes important to you because you've put so much on the line.

Should we only make rational decisions, the only thing we would do in the case of a price tank would be to just take out whatever we can, and think of a new investment strategy.

But, as it has turned out for us, considering ourselves rational is the most irrational thing we do as a species.

I've come up with a theory regarding the above described sunken cost fallacy and abusive relationships.

I've never read this anywhere, I've just come up with it myself, so don't quote me on this.

But if it's hard for us to minimize our losses from a bad investment just because the investment was big enough, wouldn't it make sense that it's hard to abandon and abusive relationship because of the victim party's large investment into said relationship?

It's often wondered out loud by people how it's weird that abused partners don't just up and leave. Well, I've always felt that it's obvious they're not thinking logically. So, something has to be there that's causing the seemingly irrational behavior.

So, my theory is that when the abused person gets beaten in a relationship, that person makes an unknowing investment into the relationship, since suffering from violence and other forms of abuse obviously takes energy and emotional resources, which means that it's an involuntary investment into the relationship.

The way our relationships work in general is very much in line with the sunken cost fallacy; the more we invest of ourselves, the more important the relationship becomes to us. A very common problem in relationships is that there's a lack of balance, since the person who does the most, cares the most. And sometimes the other person doesn't get to do enough to care enough, and eventually the relationship goes sour.

A functioning relationship therefore requires a 50/50 from both partners. That way, it's equally important to both.

So, would it be an impossible thought that when someone is suffering from violence from his or her spouse, it forces that person to constantly think and ponder, fear and suffer so much emotionally that the investment he or she makes becomes so big that the person actually, completely, counterintuitively, becomes extremely attached to that relationship?

If it's true when investing, why not when in a relationship? Economics and love are closer to each other than you think, by the way.

What do you think? Am I completely off base here?