I work with stallions, and NEVER have this kind of behavior, even around mares. This could be a hormone problem, but hormones don't tell the whole story. Stallions should have manners just like geldings, and that goes for geldings that think they are stallions. Get an experienced horse handler with good references to help you at your barn. If he is acting disrespectful towards you, on the ground or EVER, you need to fix it. He must learn that YOU are the lead mare. Nobody messes with the lead mare. Be safe.