PearlyBaker, I read through your other thread, and you don't say whether you have tried MC in the past or whether either of you did any IC.
I'm wondering if your WS is consumed by guilt and shame and that's why has pulled away but doesn't want a divorce. If he's anything like my WS, he doesn't want to face his guilt head-on, so he's sweeping the emotional stuff under the rug and playing the part of "good husband" by doing extra chores, nice gifts, etc. In his mind, this might be his way of atoning and "fighting" for your love. Guilt and shame are powerful forces, and they are unhelpful past a point, but for people who are avoidant, they turn into a barrier that prevents them from dealing with those feelings in ways that help the BS to heal.
It's totally unfair that this puts the burden on you to take action, but nothing about infidelity is fair. I would suggest that there's no harm in trying MC, if only to facilitate open communication about what each of you has been experiencing as reality for the past 6 years. I would also strongly recommend that you do IC in parallel (and so does your WS). You need a place to process your own feelings independent of his.
If all of that fails to improve your situation, then you know you've tried everything and it's time to walk away.
My personal opinion from what I've read about your situation - I think you're both sleepwalking through your lives, going through the motions because you're afraid to walk away. Considering how early in your marriage he cheated and that it was an LTA, compounded by his lack of self-awareness and the failure of R so far, I don't see a lot of reason to be optimistic. That said, every couple is different, and people on SI have bounced back from equally terrible situations, so my 2 cents are worth exactly that. :)