I have been comforting myself with the fact that since separation, H has spent very limited time outside of work with OW. They've maintained their lunchtime walk status quo. Is it actually bad that they aren't heating up more? Cuz how can they crash and burn if they don't get off the ground?

Theoretically, if their relationship remains buffered from everyday realities of real life living of relationships with all its ups and downs, then lala land thrives longer because it remains a fantasy and they each approach the other on the best of terms, like when you first date.

I know that bursts your bubble. Still, it's a general rule, but doesn't mean everything always works that way. Who knows what else can happen that may affect your sitch?

As it is, affairs take the amount of time they take, period. It can be three years or more later and there's a midnight phone call, but like Dodger pointed out, you may not want to take the call at that point.