Originally Posted by JustAGirl
Ask her to let you use her phone, you can't find yours....
Watch her reaction!
This... but don't let it go at her simply refusing to not let you have it. Insist, calmly... don't let it go until the confrontation happens. Then whether she gives it to you or not, have the discussion about who she's been calling at this number. if she gives you the phone, show her the number. If she doesn't, just flat-out ask her. BUT...already know who it is by calling them, paying for reverse lookup if you must. Know what you're dealing with, and get it on the table. Calmly! because if she denies or lies, you know what the deal is. If she tells you, maybe even explains it (not gonna happen), then your dialogue has begin and you can begin dealing with the situation.
Think through what you want, in advance of all this...through all scenarios (ie, if she tell you she's having an affair, what would you do? If she denies it, what would you do? If she admits to "talking to someone", what would you do?...)
Be prepared for all possibilities. Good luck.