Christ really paints a great picture for us through this verse on how many times you should forgive someone.
Matthew 18:21-22 (KJV) Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times? 22 Jesus saith unto him, I say not unto thee, until seven times: but, until seventy times seven.
I believe that Jesus said seventy times seven as meaning countless times, friend. You should forgive countless times. And just think of how many times you have been forgiven by God. Countless. So think on these things as you are given the blessing of forgiveness towards your husband.
Have the same mind as Christ towards forgiveness.