It must be horrible to have gone through that, I can only imagine. You need to heal from the hurt first. And that means doing whatever YOU need to heal. Getting closer to God, trusting that He knows what you are going through and that He has a plan to prosper your life and that He will never leave you nor forsake you.
I don't know why we go through heartache and pain like we do, but it is true that suffering creates character. For your life and for your husbands, God sees the beginning from the end and is working something out.
I don't think you should keep in contact with your husband while you heal. I don't think you should be his "friend". He doesn't sound like he really realises what he did to you or is fully sorry.
I'll tell you something about cheaters. They don't appreciate what they have. They don't care about the other person until they realise they may lose them forever. At this moment, your husband sounds like he thinks you will always be around anyway, that you are sympathetic to what he's been through in the past and that you love him and will always be his friend.
This all may be true, but he needs to THINK that he no longer has you in his life. He needs to really lose you and contact with you, in order to really realise what he had and what he put you through. People just don't care .. when they think they have you always. - That is, unless God gives them a revelation. (Which He can.)
On the road to Damascus, The Lord "pretended" to be continuing on with His journey so the two He spoke to would constrain Him to come in. He knew all along that they would but it's interesting that He did that.
Sometimes, we know we will always love someone, we know we will forgive them and be with them.. And God knows. But THEY don't have to know... Not until they've reached a certain point where they are truly sorry, anyway.
I hope this makes sense, it's a bit of a weak example to use but I hope you can understand what I am trying to say.
Breaking contact helps YOU. It means you can focus on God and healing. But it is also giving your husband a chance to repent and realise how he hurt you.