Wow that is a tough situation. You must get both sides of the story so you can make an informed decision. If this man did assault your daughter then definitely drop him, and press charges. You might love him but if he did this then he is a piece of crap. From what you've said I feel like your daughter is acting a little suspicious or maybe you feel as if she is lying in some way. If you never had even a hint of this situation then try not to blame yourself too harshly for it. How could you have known that this would happen? If what she says is true then both of you should seek therapy, you both need to learn how to cope with the situation and move on so that your relationship can be strong again.