I'm glad that although you shy with other people that you aren't with your husband and were able to articulate quite well it seems how you feel and what you want. I hope he comes to see in time that the other woman was not being caring at all.
Nope, no reason to make an effort to be poly if you're not, I am glad you're clear on your boundaries and not interested in being talked into doing something you aren't interested in. Good luck!
Happiness will never come to those who fail to appreciate what they already have.