How do you support people close to you who are going through a divorce?

A very close friend of my husband and I has made the decision to divorce his wife. This friend is a very big part of our life, and he has been unhappy in his marriage for a long time. We are not as close with his wife, since they choose to spend a lot of time apart, but I have still known and cared about her for years- and I consider her a friend.

In any other circumstances that would be emotionally difficult (say, a loss of a family member rather than a divorce), I would without a doubt reach out and offer support and an ear to her, as a friend. However, I feel that I am hesitant to do that in this situation and I’m not really sure if that is right or wrong.

How do you approach something like this, without being disloyal to anyone or somehow putting yourself in the middle?