Is he cheating?

So I found messages from my partners laptop with a girl at his work messaging eachother on Skype flirting. I'm 37 weeks pregnant and this happened about 2/3 months ago. I confronted him and we sorted it out and he apologised and said he will stop the flirting.. anyway since then I've became very cautious of him , like being on his phone (Snapchat and WhatsApp only when I'm not there) but anyway I didn't let that bother me any more. Today he came back from work and first time in a long time he came in straight home saying how much he loves me and kissed me from behind. I turned around to look at him and seen blonde hair stuck in his coat zip... I immadietely said who's hair is that , you hugging other women?

He laughed and goes probobly yours from me hugging you there now , (bare in mind I have short hair and black hair.. )

This was quite long pieces of hair stuck in his zip, plus I would of felt it coming out of my head right ??

I got up and went to make dinner and tears just started to come down my face. He came up and asked what's wrong and I didn't wanna argue so I said doesn't matter, but he grabbed me hugged me and told me to tell him. So I did , I said I feel weird , and it doesn't feel like it was my hair.. and he imaddietely started to shout at me how much of a psycho girlfriend I am.. that I'm such a insecure bitch.

:( this has hurt me , because not only do we never have sex anymore , when we do , it doesn't even feel like he is enjoying it.. :(

Am I over reacting ? :(