Oh LNM, I'm so so sorry to hear this, how heartbreaking
. It is too much. Normally in a break up these things happen slowly, you get the relationship going bad, then an ending, then they find someone, then they start a new life, and you do too at the same time. It happens in stages, and we can adjust and let go in stages too. But you've smashed from happily married family life to betrayal and OW and pregnancy in what, two weeks? It must be so disorienting and just hellish.
Two things tho: 1) presumably it can't get any worse than this, tho that's small consolation, 2) that progress you were making, it's not lost. You might be back at square one, but you know things got better over the last few weeks, and so they will this time.
Sending you love and hugs x x