DEAR ANNIE: My wife and her sister have always had a close but delicate relationship. They can talk for hours, laugh about old family stories and check in on each other several times a week. But every so often, something shifts, and my sister-in-law becomes sharp, angry and deeply hurtful toward my wife. The source of it almost always goes back to her divorce.

Even though the marriage ended 15 years ago, she still carries enormous bitterness toward her ex-husband and blames him entirely for the breakup. During their marriage, however, we grew close to him as part of the family. More important, he is the father of our nephew, and because our nephew lives with him, we naturally see him when we travel to visit. Sometimes that means sharing a meal, catching up for an hour or sitting together at one of our nephew’s school or family events.

We are not trying to punish my sister-in-law or dismiss what she went through. We care about her very much. But she insists that by continuing any relationship with her ex, we are being disloyal to her. She says family should stand with family, no exceptions.

At what point does loyalty become emotional blackmail? Are we wrong to want peace with both sides, or does supporting her mean cutting him out of our lives for good?

• Caught Between Love

and Loyalty

DEAR CAUGHT: You are not wrong to care about both people. Divorce may end a marriage, but it does not always erase every family bond that came with it.

That said, your sister-in-law’s pain is hers to work through, not yours to manage by cutting people off on command. You can be kind to her without signing a loyalty oath. Tell her gently that loving her and maintaining a cordial relationship with her ex, especially for your nephew’s sake, are not mutually exclusive.

If she continues to lash out, boundaries are in order. Love is important. So is peace.

DEAR ANNIE: I am a grandmother with a heavy heart. My family has always been rooted in Christian faith, though over the years we have belonged to different denominations. We have always believed that while our worship styles may differ, our love for God and for one another mattered most.

Recently, one of my grandsons has taken a very different view. He believes his denomination is the only true one, and that the rest of the family is living in sin. Because of this, he and his wife have decided that no one outside their church may see their baby. I understand parents have a right to make decisions for their child, but this one has left me deeply hurt.

I am grieving the thought that my great-grandchild may grow up never knowing his great-grandparents, grandparents or the larger family that already loves him so dearly. My grandson knows how heartbroken I am, but so far it has changed nothing.

My question is this: How should I handle this going forward? Should I continue to acknowledge birthdays and holidays by mailing gifts, even if we are shut out of their lives? Or would that only make the pain worse? I pray that one day he will remember that family love should count for something, too.

•Heartbroken Great-Grandmother in Florida

DEAR HEARTBROKEN: This is a sorrow no grandmother (or great-grandmother) should have to carry. Your grandson is entitled to his beliefs, but love should not need a membership card. Send the gifts if it brings you peace, not because it guarantees a door will open. A small kindness has a way of waiting patiently on the doorstep of a hardened heart. Keep your message loving, brief and free of argument.

In the meantime, pray for them, leave room for reconciliation and do your best not to let anger have the final word. Families have been reunited over far less. Faith, at its best, draws people closer. It should not shut them out.