Am i normal? One girl in which he wrote!

Hello..I have been divorce in 2010 and now i am remarried again. My husband hide things n lie to me very often. Recent incident was he told me on dinner table he is going for some meeting n have to drop file at one place.ll be back by 12-1 in night.i believed him.but very next day when i checked his phone where i saw his chat with one girl in which he wrote thanks for you company last night had great time with you.it seems they had joints in the cars they written n he was making plan with her for another night for drink on the wheels n when i asked him about entire episode he said he is doing such things for work purpose. And this is not first time he lied he lied me about his previous affair also n he use to meet n talk to that same lady after we got married.When i caught him he came up with some story and asked me to forget entire episode. Now i have a habit of seeing him online i get doubt that he must be talking or flirting with other female. please help. what i have to do.