I have a queer/straight relationship, and need help

My partner and I have been together for about 20yrs. 10yrs ago I had a weak moment where I went online with another woman. I messed up. Since then I have not been perfect, and have made some mistakes. All this being said, she has been interested in woman as I have been interested in men. But we have an issue with communication and trust. Where can we start to build a better relationship?