IB Snodderly has written some wise words on my thread about OP2 and they are consistent with what another friend and I are finding as our xh move on to the second OW.
It appears to be a very different relationship. In general the second OP is less obviously messed up, but when you look below the surface they are still very troubled people.
Big generalisation here but the first OW is all about passion - using the emotional high to feel good, and to get away from their existing life An escape route. Now if they don't work through the replay crisis [and I am not at all sure about these statges, as I have written elsewhere, but the crisis certainly has these elements] by the time the relationship with OW1 comes to an end they are still lost, and not at the point they can face their issues, and certainly not alone.
Snodderly described it on my thread as their being in a kind of limbo, floating on a sea, and that is the sense I get with my xh. Not going anywhere in this, can't go forward can't go back. Stuck stuck stuck. SO the new OW is a distraction, and certainly not the 'soul mate' they thought OW1 was. I think it is probably a good thing they are less messed up than the first OW. But certainly not OK.