This is a very moving and honest article from a husband on dealing with the grief and pain of his wife's miscarriages. While it can be hard to read, I think that it's a good one for your SOs, while they might not grieve in the same way they still suffer pain:
I was sad, angry and confused. Do I have any right to be this upset? Should I mourn this as the loss of a person? Am I even ALLOWED to mourn? I had no idea what to do but I wasn’t about to ask or complain, especially to a wife who just literally had the life sucked out of her. And even though my wife was lucky enough to have a great support network checking in on her, my instinct to repress everything was confirmed by the fact that no one asked how I was doing.
I felt alone and scared. I broached the subject with my wife but she was going through her own hell and I felt terribly guilty for burdening her with my feelings. The whole thing was further complicated by the fact that my wife and I were coping very differently.
Read more: http://www.ivillage.com/my-wifes-miscarriage/6-a-544002 
How has your SO dealt with their grief? Are they willing to talk about it?