When I was in school, I committed a sin and made friends with a boy who was my friend’s brother, but she had nothing to do with it and she was innocent of my sin. When my family found out about it, they forbade me to talk to her. Now I have got married; is it permissible for me to talk to her, knowing that if I talk to her we will talk about ordinary things that have nothing to do with that boy? May Allaah reward you with good.
If your talking to your friend will not result in any negative consequences such as her brother trying to talk to you or contact you and the like, then there is nothing wrong with your talking to her, because that ban was only because of negative consequences that might result from it. But it should be limited only to talking to her, and not visiting her. It is better if it is done with your family’s knowledge; perhaps they know something that you do not. Keeping company with some people may lead to damaging one’s reputation or being thought badly of, and news of that relationship may reach the husband.
May Allaah help us and you to do that which He loves and which pleases Him, and divert fitnah (temptation, trouble), both apparent and hidden, away from us.
And Allaah knows best.