I've read both threads and I am really sorry OP.
Your H really sounds like he wants defacto at least an emotional threesome or some kind of polyamourous relationship. He calls it friendship but in reality it has been playing out as a threesome, and I am disgusted he wrote about how the idea of not having her in his life "hurts so much" to you when you are hurting how much?!
It also really leapt out at me how he's going on about how you smile, you don't get broken or something to that effect and how he loves you for it, he says all you need to do is be yourself, but actually very specifically describes the optimal (for him) version of you, who shakes herself off and powers on, who can withstand any suffering(maybe he feels more guilty if he lets himself think of you as weak or broken), if you are that unbreakable and sunny, OP, it's not as much of a big deal to break you a little bit compared to someone who is "truly" vulnerable (like OW 
)
To be honest I could see how your friends are not as angry with OW as with H, my first husband had an affair and I knew he fell for someone and I was 100% sure it was a phase and it was purely emotional and he'd work his way out of it (because I had been there myself). Well even though he met the OW when I was 6 weeks pregnant with my 3rd, he managed to convince her that we had lived like brother and sister for years, and because I didn't want sex I "didn't mind" that they were doing it. 
We were in our mid-late 20s, we had sex most days! Throughout his affair as well... OW was 3 years older with kids of her own, and she had left her H because he cheated with his PA! So you'd think she wouldn't buy it, but there are situations where people would believe the most ridiculous shit because it aligns with their true wishes.
Anyway, we came across each other in some clubs and music venues (ex was a musican and she was too), and twice even found ourselves at the same table at a dinner party, and she always gave me these weird pitiful and guilty looks. My ex was Catholic too, and I was absolutely sure that he wouldn't actually go through with physically cheating, and I believed him when he implied it was an infatuation.
Anyway, it went on for 18 months, and then by accident I found out that he had lied to me about something completely unconnected but significant. Only then it struck me that if he did lie to me about that, he could have lied about other things, and I actually found out the OW's number, rang her and asked if they had ever slept together.
To say that she was stunned is a big understatement. She even hinted that she had a miscarriage from him...to cut a long story short, I wasn't even that angry with her, I chucked him out, but even though you can see he didn't come across well in this story the first thing he pleaded was that he was cutting her out of his life and would never see her again (and followed through)
I couldn't stay with him after that anyway, also discovered that EVERYBODY knew, except me....it's been over 15 years now and water under the bridge, we are like distant relatives now, relatively friendly. We didn't co-parent though, once I left he eventually re-married and had more kids, and I emigrated...