Today I'm wondering if I should somehow let my H know that I wouldn't necessarily consider this OW a dealbreaker.
What good would this do right now?
He is not interested in reconciling at the moment. So telling him that him treating your marriage and commitment disposably isnt a dealbreaker for you is not going to bring him closer. If anything, its going to show him that youre willing to do anything to SAVE this marriage. Im guessing if this statement had any impact, it would only INCREASE his waywardness. I dont think that doing anything to suggest that you are waiting around as a plan B is going to help your cause.
Now, that said, decide for you whether this is a dealbreaker. And consider your values, your boundaries, and your needs. Then keep to them.
