Do you consider this cheating?

Denise
My boyfriend stupidly added his email to MY iPad and I found emails...hundreds of emails from sex sites and they were all from before he met me but one was from an adult site and he was talking to a girl while he was with me and even sent her a pic from MY house. 
She's in a different city and this site is a hook up site and who knows what he was gonna do. I don't know if it was just talk sex or what but wtf?!! He can't talk to her now because I have his debit card as he can't pay for his membership to talk on there anymore. 
What would you do?