Big life problem...PLEASE HELP...or give opinion!?

im due my baby in less than 10days me and my bf have been together 3years we have had our ups and downs but he was delighted wen i got pregnant... we decided to move in together when i was 5months gone but we started having little fights due to living together for the 1st time and my hormones, i started getting suspcious as he was never home and really distant eventually after many fights i looked in a spare ph. only to find msgs between him and another girl.. my heart broke i called him up (he was out!!) and asked whoshe was he just said wat?? and freaked at me for looking in ph he said it was his friend txting the girl.. i didnt believe him so i rang the girl when he hung up asking did she no my bf and she said yes he is beside me ill put him on un aware of who i was! he hung up!! so we faught and faught he denied it i text the girl she told me she had been seeing him but had not slept with him the msgs in his ph stil haunt me the way he talked to her asking her out for drinks the pics everyting. we sort of worked it out he said sorry im9 months preg now but i put on a fake smile tohimand everyone but all i tink about 24/7 is him and her the msgs and all the tings i don no like does she live near (i tink so) what she looks like etc. i love him but i dont tink i can get over this i dont no what to do i feel lost and alone and i cant talk to him about it... its so hard now with the baby too