so i logged into my boyfriend's Snapchat to keep his streaks while he was grounded. i was curious about what he was talking about with a girl we've already had issues about, so i looked. i found him and her talking about things that a guy with a girlfriend shouldn't be talking about. i was super upset, but i had to wait two days to talk to him about it, because he was still grounded. he answered me today, apologizing and playing the pity card (like he always does when he knows he's in trouble). I'm slowly working it out with him, but i really want to talk to the other girl. how should i approach the topic without her getting defensive and angry at me and lashing out later on?