Husband cheated on me 3 months before we were married

My husband cheated on me 3 months before we were married I didn't know anything of the infidelity until the night the child was born. This hurt me dearly but at that time I decided to stay in my marriage. Now moving forward 4 years now I have never met my husband's son but I do take him there to see the child but I'm not allowed to get out of the car I am told that I must go around the corner and park. I don't feel that this is right I don't know what to do because this is so hard for me this is my second marriage and also my husband's second marriage and I just feel like why am I a secret she knows that we are married but I feel that she uses the child to control my husband. She told him that she would not allow him to see the child if I came with him.

Yes, the fact that you're left 'out in the cold' when it comes to your husband's actions concerning his son and that he cheated on you just prior to being married, should tell you where your marriage is at. It doesn't matter if this woman uses the child to control your husband, what does matter is that he lets her do it.