I feel i maybe able to help a little here- So when I was drinking apparently I flipped out at him- I smashed a bottle and held it against my neck and my arms and stormed out of the house- I punched his eye and he had to tackle me to the ground- (according to my boyfriend- I blacked out). I did it because apparently I saw some girl on the Tv and I saw him look at her and then boom- In the morning I broke down after he told me what happened- I felt guilty and like I didn't deserve me- He cuddled me and told me he was scared and that he didn't ever want me to be like that again. I wouldn't have been able to live with myself if he didn't forgive me. You two are getting married someday so I would advise in your own time trying to listen to her- cuddling her if she will let you- trying to get her to open up- Do try counselling if this doesn't work. But beware she may not want to open up whatever is bothering her to someone else. Just try and be there for her as best you can- she is obviously going through something and snapped at the wrong person.