Hi.
What he did was probably a natural response to her activity. That doesn't actually indicate aggressive to me... but protective.
How old is this boy?
Sounds to me like you just add him to your flock and treat him like a rooster, though I'm suspecting cockerel.
Basically, he needs to respect your space. Roosters are not pets and don't like to be treated as such. They don't want you to hold and pet them. You should walk directly through the path of the boy. He must step out of your way as a matter of showing respect for your space.
You could even chase him just a little. In the chicken world fear equals respect. Gentle moving and coddling does not equal trust. It equals that they don't have to fear/respect you.
This protective stage usually hits around 8 months old in my experience. Cockerels will usually go after who they see as the weakest. If you have small children it will be them. They usually give my dogs the stink eye first and then escalate to attacking when the dog passes by. Just yesterday I got my first good attack from my favorite coddled boy. He was coddled before I knew better. So I put him on the run. He got my leg while my back was turned. He has recently become my only breeding age boy. So I think he decided I was the next that had to be taken down.
I am an animal person. And injuries hurt but don't scare me. So I will pursue giving him a little schooling to see if he gets to stay past this breeding season or not. I realize though, with the experience I have... that there is more to the story than meets the eye. For example... no matter how many times I call him a rooster, what he actually is, is a hormone raging, horny, semi out of control teenager. If you have any experience with teenagers and seeing how things effect them you can see the root cause of the behavior. Every animal at a certain pubescent age becomes a little wild and testy. So this is no different, IMO. Some can be corrected and live happily ever after. Some will raise cane until the day they die. Every single one of my birds no matter what breed is an individual, just like my dogs and my kids.
You may have to experiment and see what works for you. I like a squirt bottle with a nice long reaching stream. And I always use something to extend my reach... like a broom, oar, stick.... whatever I can get my hands on. I don't swing it at them or anything... just use it as a long arm to heard them where I want them to go. It helps a lot. The other poster made good suggestions except for me I would avoid the handling. Gotta try what works for you though.
The time I do insist on handling my boys is at roost. If anybody pecks me, they get packed back. Roost is also the best time to catch birds if you need to. They are very calm and docile after they have settled down for the evening or before it's too light in the morning. They can't see well in the dark and being quiet and still is one of their defenses from predation.
After some maturation... they call girls to treats, dance for the ladies... quite fun. But boy am I different at 43 than I was at 18! You get the difference.
I will see if I can find another good post I saw to share with you for the technique in a bit.
Good luck!