don't know what to do.

I'm with my husband 10 years. we are married nearly 2 years. we have a daughter who is nearly 2. a few months back I found messages of a sexual content on his phone while we were on a little family vacation. I was leaving him. was packing my stuff and he stopped me. we talked and talk and he made promises. I stuffed from depression and anixity and I have some weeks of highs and other weeks of lows. I'm having a low few weeks and he has retreated back into himself. back not helping and getting snappy when I lose my cool instead of helping me out. I don't know if it's the depression talking or what. But I don't trust him and I don't know how I can trust him. right now I just want to rip his phone from his hands and go through it. I want to scream and shout. But I know I cant. why did he do this to us. why did he ruin us!!!