This is an interesting beginning. I don't know what direction you're planning to take it, but I think once Henry has had the affair with Maria, he's beyond redemption -- at least as a potential match for Fanny. I think you've captured the characters really well. Henry is as cringey at the inn as he was that day at MP when Edmund was hiding behind his newspaper letting him harass Fanny, I'm glad to see you exploring his character, I find him fascinating.
To answer your question, I don't think Henry feels he needs to "escape" London or Maria because as far as he's concerned the affair is over. "When he returned from Richmond, he would have been glad to see Mrs. Rushworth no more." I guess he could have just left London once the rumors started circulating; it never really made much sense to me why he eloped with Maria and the only explanation we get is that "he could not help it."
I'm looking forward to seeing where you go with this.
