My youngest daughter recently split with her husband after discovering he'd had numerous affairs - including one, many years ago, with her sister! My elder daughter has tried to apologise for what she did, but this hasn't been accepted. My youngest daughter is even refusing to speak to me because I won't take sides. I can't understand her reaction - after all, the affair was a long time ago, the marriage is now over and she has even remarried. This is dividing our family - why can't she just move on?

Susan advises
You think that because your daughter's husband was unfaithful many years ago, she will be over the betrayal - and that because she has already found someone new, she will have recovered from her failed marriage.

But the discovery and the divorce are both very recent. She's not had nearly enough to time to get over them - in fact, because she remarried very quickly, she probably didn't get the chance. One needs a period of time alone after the end of a relationship to think things through, to learn lessons, to heal wounds.

Your daughter hasn't had that time, So she's still hurting very badly - and as the ex-husband isn't on the scene for her to lash out at, she's only able to lash out at the other main player in the tragedy - her sister - and at the supporting cast - you.

You need to support your daughter to work through her break-up and the previous infidelities - as a starting point, write a letter expressing your concern and love, telling her you've written to me and passing on my comments. If she's too hurt to understand what's really happening and rethink everything, then there's not much more you can do. You can only wait until she's recovered - and hope that when she does, she feels able to forgive.