Oh, this is good! This is exactly what came across- Teresa starts everything but then Patrick takes over and Richard is drawn into it and chooses not to fight it. I see we are on the same page there ;)
I can only watch the Sharpe series in small parts because there's too much war and costumes and canon's and all of that for my taste (I haven't gotten any farther than "Sharpe's Honour" I think) but I was quite pleased with Teresa. Though there role is a stereotype- strong woman but can't resist the hero (who of course is a man) it's a lot better than many things you see here on TV and I think it's what you mentioned, that she is strong as a woman (and a mother) that makes her interesting and that she's not some strange amazon who wants to be a man.
Sorry for the gazillion typos in the other comment, was in a bit of a hurry...