Very good ideas my friend. I think the same could happen.
For your option 1 i can see maybe a "roadblock". (Only If its something P&P put it in-game)
1st one is that we choose to go on the trip and try an fix the relationship. That will close the cheating route with Fred (Most likely not happen)
2nd one is that we go on the trip but that Lily/therapist can convince Nick to let Fred come with them so them all can start over.
I don't think of an open relationship/marriage would happen, more of a break-up i think. So i think stay, try, fix or break-up. Is the option we get.
Wish thinking:
How HOT wouldn't it be if Fred asked Lily to separate from Nick and become Fred's wife? Nick getting a new step-mom
Just some thinking from me but what P&P have in store is not easy to say. We just have to wait and see
But we all know that this "storm" opens alot of possibilities on what could and can happen.