I don’t know if your H is protecting OW… He is probably protecting his ego. He is ashamed to admit that it didn’t work out with OW. I don’t see why he could lie about not being involved with OW any more. If they are no longer together, then I see why he is not doing anything about the D.
Like Job would say, sit quite and the answers will come to you. Keep doing what you’ve been doing, no R talk. Don’t bring D subject unless he asks.
M:50 H:52 S28 (my S from previous marriage) M:17 + 3 BD: 06/12 S: 06/12 - H works in another state