Maybe this is bothering you more than it is her. It has been 20 years for her, if she hasn't dealt with it by now she never will. Are you willing to watch everything you say to her in fear of upsetting her? Think about it, she is independent for a reason. She can make it on her own if she has to. Talk it out with her and see how much or if it still really bothers her. This way you can form a trusting relationship. The best to the both of you.