Found out bf was talking to other girls online by searching his phone. How do I bring it up?

Given that Tinder is a matchmaking application and not a let's-make-friends application, it's logical to assume he's looking to hook up with other girls. Is this a deal breaker for your relationship with him? If it is, don't even explain yourself - dump him. Once he knows what you know and how you know it, he'll hide it better next time. Consider this your big chance to get out now and find someone who won't scour a dating app for new booty.

I feel like there's no "perfect" way to do it. Unless you know what the conversations were about, then you have no idea if he's done anything wrong or not. But if you are set on talking to him about it, the best way is just to be honest and voice your concerns. I'm sure he won't be happy that you were checking out his phone, but maybe he can set your mind at ease.

i agree with @missblueeyes :D damn! those boys just don't know how to get contented >.<

I feel you. I also caught my bf doing that but he keeps on telling me that he's contented with me. Lol. At the first place, he won't be talking with other girls if he is and what will hurt you the most is you will think of the what if's like what if, the day will come that bf found already someone better. so one day, I opened up that topic and we just end up arguing.