Answer:
Firstly dont get cazily peregrine and not let her txt him again. In a fun way show a but of jealousy, girls like this. If it really bugs u just tell her that u aren't comfortable with it and ask where u stand while she is txting him, does he like him too? Are u on the verge of braking up? Or is aleverthing okay, she's just being friendly (I bet on this one)? Good luck ;D