Don't just read about self defence. See if you can find a women's self defence class. I did. It was fantastically empowering!!

I am surprised no one has mentioned this before, but maybe another dog? A bigger dog?

Be on your guard, keep your doors locked but don't be afraid in your own home. Take precautions but enjoy your new life. He seems to be setting a boundary for himself and not getting real close to you during your encounters. Ensure that is maintained, don't let him come any closer. You'll learn how to do that in the self defence class. What was truly funny in my class was a 60 year old woman was able to use just her voice to keep the "padded attacker" at bay, he couldn't get near her to grab her. She was hugely powerful just using her voice.