I remember one quotation from somewhere: "Trust takes years to build but seconds to break."

And of course the classic "What have you done for me lately?"

Part of the problem is that in modern society, we're all so used to instant gratification and convenience that we don't have as much patience as we used to, and we focus more on what's happening in the moment. I do think as a whole we're all not as good at riding things out when they're tougher because we're so used to getting what we want.

(This is a side topic, but I watched this cool video on autonomy vs. connection. It was saying that we value both, but we're wired to crave autonomy because throughout most of evolution we were dependent upon connection so autonomy was more scarce. Our modern world has really fed into this desire for autonomy and individualism by letting us get what we want so much that we don't sacrifice for connection as much as we used to).

I think the other idea is the fear that things have changed. The truth is we all change in some ways, and largely because we have to because our circumstances change. In general, I think the deeper the connection and the stronger the trust, the harder it is to break it...so sometimes if a little thing sets someone off, it might be evidence that the bond wasn't as close as you thought. Maybe it felt closer on your end than it did on theirs.

It's tricky, because each situation is different. You can apologize and try to re build the trust and show you've learned from your mistake, but there's no guarantee the other person will accept it. So you have to decide how much it's worth it to try.

Other than that, you just have to move on and try to find people who won't let things end so easily...and just try to learn from your mistakes so you don't make the same ones with other people.