Cheating husbands

Hi, I'm looking for some advice as I'm totally lost and heartbroken with no idea what to do. I have a 1 year old son with my husband of 8 years. The past few months have been so hard for us. My husband had a mental breakdown and is still suffering with severe depression. Last night I discovered that he's been meeting strangers off an online gay dating website and uploading explicit photos of himself. I Confronted him and he broke down saying he was a mess and it was a stupid mistake etc. He said he's been feeling lonely as things haven't been right between us while this has all been going on and he was craving attention. He's begged me for another chance but I don't know how I can forgive something as extreme as this?? He also doesn't want me to tell anyone as he'll lose everyone but I feel like he wants me to just get over it and pretend it never happened. I don't know what I should do. Thanks in advance.