What would you do if you had access to ur spouses x girlfriends/boyfriends email address?

yeah, dont send her a message. you have him be happy. sending her a message would be super immature. dont stoop to her level. i know its easier said than done, but dont do it. let bygones be bygones. just think if you do that shes going to retalliate. she may even try to mess up the wedding or come back into the picture. dont put yourself or you fiance through that.