Help please?

My husband of 6 years cheated on me 6 months ago...we still together, but I cannot forget everything every single day . He is showing me love and respect day by day now, but Im still thinking he is going to do it again...even when he tells me it won't happen again.
My heart fell in pieces when he told me we needed to get apart because he wasn't happy and a few minutes later he told me there was someone else. I fought for him at the time because we had so much and I thought it was beautiful before this happend and I also knew his trashy friend had a lot to do with it because he did not like me at all and he liked the nasty girl the my husband was seeing. I didn't want to let her take everything I had so I gave him a 2nd and last chance... we moved out of the state and he hasn't talk to her in months but I can't forget those weeks of pain. He also says they did not have sex but messed around it just hurt so bad sometimes. I love him and we are expecting our first baby but I don't know how long is gonna take for me to heal my heart.