Think what the possible factors may be to why she needs comforting
Could be someone she knew that passed away? Did one of her female friends accuse her of something? Or maybe you can recall if it was you that gave her the hurt.
A hug makes every difference
Believe it or not, a hug can make a huge impact on your wife at tough times like this, be telling her not to worry and even giving her that kiss on the forehead to remind her that you love her.
Ask if she requires any assistance
does she need anything? A glass of water? If she is crying and she says no to water we would suggest you bring some anyway and maybe take over any chores that she was supposed to do around the house/picking up kids.
She wants space
If you requires space then do not force your face into her space, the best thing you can do is give her that space and let her come around herself.
Never fight back
Is she mad at you? The worse thing you can do is start defending/fighting back – listen to what she has to say and agree followed by leaving the room.