It is soooo early...
... and I don't want to frame this like it's going to be some slog up a mountain.
You will NOT feel this way forever.
Reading your post, it seems like you've made an amazing amount of progress in 6 short months. Maybe it's time for a plateau. As long as there is no major backsliding (further dishonesty/infidelity) think of it as a breather.
This is a walk back to happy, not a sprint.
It needs to be a walk because there's a lot to resolve on the way.
Infidelity doesn't happen in a vacuum.
Contributing factors are no excuse, but they do exist. 'Pre-existing conditions' will also have to be addressed, along with the trauma of the infidelity.
'Meh' is a place. Sometimes it's permanent, but not always. Sometimes it's just a temporary 'Meh' while your subconscious works out all of the territory you've covered.
We are 27 months out from DDay, for an incident that happened *years* ago, that had a partial/vastly minimized DDay when it happened. So two DDays, same incident, but years apart, and DDay2 actually ended up being the 'real' DDay. It was classic: denial, minimizing, gas lighting, trickle truth, the whole bit.
We had all of that to work through before we could even begin to work on the infidelity, and then on the issues in which it was embedded.
It just takes a while, and it's a roller coaster. Don't be surprised if you visit all of the other emotional terrain again (and again) as well. It's not called a roller coaster for nothing.
And some triggers will hang around for a bit and raise their ugly little heads at the most stupid of times. I just wrote a chapter book on here about the stupidest trigger, lol.
Don't throw in the towel just yet. If you are both trying, if your spouse is in IC of his own accord, if he is being sincere and genuine, there is hope.
There is hope that the love, affection, hope and trust can return. (((hugs)))