There's a fine line with having friends of the opposite sex/coworkers, when you're in a committed relationship. I don't think it's appropriate for her to be emailing and tending her phone while she with you at home. If you email him, I think this would make things worse. She also shouldn't be telling him problems between you/her and instead should be working on your relationship.

Tell her you're not comfortable with this level of contact. Do you think she told him that you were breaking up at some point?? She should be bonding primarily with you. Maybe couples counseling would be a good idea.