Is this cheating?

I was seeing someone long distance for about 2 years. I broke it off because he wanted me to move to where he lived. I missed him and realized i didn't want to live without him so i reconnected and started flying to see him in October, November and December. We did not make anything official because he said he wasn't ready but we could work on it. He finally asked me to move in with him and i packed up my entire life and told my daughter whos 8. Then last night i get a phone call from him saying he had to tell me that he had been dating someone and she just informed him she had an std, he got tested and he was positive. I was devastated! I had asked him over and over if he was seeing anyone and he always told me no. Now he says we weren't in an official relationship yet and he broke it off the end of November, apparently it lasted 6 weeks. Im upset because his mom even knew about her. I feel betrayed. He is 49 and im 52. This girl was 23! He said he had no love for het and it was an infatuation. I feel like even though it wasn't official, he cheated on me in a way. I spent the day at a clinic being treated for std and im humiliated. I am angry, sad and so confused now. Do i tell him to kick rocks? I think it will be hard to trust him.