I have heard that statement many times over 70 odd years referring to both humans and animals, so if it is true just what happens? what fails? how? and why?

bonding mechanisms through bio-history have been strongly shaped by reproductive successes, and failures

Presumably stress exacerbating existing health problems.

bob(from black rock) said:

I have heard that statement many times over 70 odd years referring to both humans and animals, so if it is true just what happens? what fails? how? and why?

I’ve seen people go downhill quickly when their significant other dies. I take it that it’s depression (lack of desire to live) coupled with poor diet (possibly including alcohol), and failure to respond quickly to significant health problems.

There is a condition called Takotsubo cardiomyopathy which often occurs after emotional stress, that is also known as broken heart syndrome. Until you do an echo, it presents like a heart attack.

Partner, and offspring, often involve an investment, a very substantial investment.
That ‘m are internalized with a rank of importance similar to feelings/instincts of the worth regards self is not unsurprising.

There’re protective instincts involved, and the mechanisms may not distinguish types of ‘failures’.

not surprising, or unsurprising, rather

/* broken heart syndrome. Until you do an echo, it presents like a heart attack. */

After you do that, though, it no longer presents like a heart attack!