Adapted from a recent online discussion.

Dear Carolyn:

When someone dumps you to stick with his plan of grocery shopping with his ex after you had stayed for the night — it's time to quit trying to make the relationship work, right?

— Mopeyville

Maybe he's got guacamole in his fridge and she's a tortilla chip connoisseur.

If you're always the one making the effort, and this is what it took for you to see that, then this hint to call it quits is actually one of those very well-disguised blessings. CGI-quality disguised. But still a blessing. Make an effort for people who make an effort for you.

Carolyn:

We have a long history, but, ever since they broke up, it always comes down to his "friendship" with his ex. Our relationship was built according to his terms. It's basically one-sided 99 percent of the time.

I get the gist, that our relationship is very close to friends with benefits. I knew going in, that was what I would have with him—but he knows that is not what I want. He can't understand that it is not easy for me or why. He acts like I shouldn't be having feelings for him. Apparently it doesn't affect him at all if he doesn't see me for a month.

I feel frustrated, sad and angry not knowing how to deal with my feelings and knowing he can just disregard me like this by not rescheduling his "plans," as I asked him to do for the grocery-shopping fiasco.

In a way I blame his ex for who he is now, because he lived with her, and he has changed. He doesn't seem like the person I knew years ago and I miss his old self.

He said he misses the old days, too, but it is confusing to me because we will never get that back.

So I'm just trying to go on with my life and hope the awful feeling goes away.

— Mopeyville again

This isn't going to sound credible, but I'll say it anyway: Stop taking this guy's indifference personally. Throughout your letter, you're saying that you and he just don't have what you used to, don't get along the way you used to, aren't who you used to be.

So, end it. Accept that people change, accept that it's over, and accept that not fitting anymore is a perfectly adequate reason for ending a relationship; it doesn't have to involve any judgments about someone not being good enough or caring enough or whatever else, or a girlfriend changing him, just because you need to blame something and put your anger somewhere.

It's not your fault, or his, and it's certainly not his ex's. You.two.just.don't.fit.

Now, once you've rolled that into a decision to stop calling this guy, the next step is onerous but strongly advised: good therapy. You've agreed to be treated indifferently by someone for, apparently, a pretty long time. Please find out—and fix—the underlying reason for that, because the first thing you bring to a relationship and the last thing you have to count on when it goes wrong is: You. That's it. Make sure you're able to see yourself as a person you can count on in the clutch.

Email Carolyn at tellme@washpost.com, follow her on Facebook at www.facebook.com/carolyn.hax or chat with her online at noon Eastern time each Friday at www.washingtonpost.com.