How do you get your boyfriend to tell you he's gay when you already know he is?

I know my boyfriend is gay but he wont tell me himself. Last month i went to football with him and his phone was left in the car with me it went off so i picked it up and looked at it to see who the message was from I wasnt going to read it and when i unlocked his phone this message from a girl was already up. This girl is a good friend of his i was reading through this and I saw a lot about him talking about how he misses being with a guy how sex is easier with guys and all of this he even said he misses being gay. He tell this girl he loves. I ignored this and thought he was looking for attention. He came back to the car and knew something was wrong because it looked like i had been crying I couldnt tell him that i knew so started a conversation about how i didnt want to loose him and everything kept dropping little points about being gay and gay people.

Today i was fixing his laptop and opened up the internet I wanted to see if there was any more proof of this. I found another message to a girl saying that last week he had told his parents he was gay. Again this has brought me to tears. He wont tell me and i just want the truth from him.

He says that he loves me and wants me and never wants to loose me or give me up and yet he wont tell me a big part of this life. Im in a complete mess here I've searched for answers on google and i cant find anything.

How do i tell him that i know he is gay and how do i cope with this. Someone please help me. I dont want to loose him he means everything to me and i love him so much.

Please help?