Mallory,
again you seem to give mixed messages in your post.
Feeling sorry for someone is not a good reason to stay and it aint love either.
Sounds like you are acting nobly but you are doing your husband a disservice in my view.
If I were him, I would hate to think my wife was staying with me out of pity.
You owe to both of you to be honest and authentic.
Leave if you don’t love him.
Have the courage or else you are playing the victim, which won’t arouse sympathy from me.
Sorry I had to say all this.
Im being authentic, possibly too critical but nevertheless.