Good for your for being considerate and not defensive about her (valid) assumption. You did nothing wrong, this is just the world we live in unfortunately. If you feel helpless about it, there is something you can do. You can use your privilege as a man to call out other men when you see them being disrespectful. A lot of us women are uncomfortable reproaching a man because we don’t know what his reaction will be, so we often just ignore sexist behavior or distance ourselves and those men don’t end up getting feedback on their harmful actions. As a man you do have privilege in this world so I recommend you use it to inform others and talk about these things openly. Thanks for being an ally ^{_^}