It's just baffling @Tahli, I just don't get it. The only thing worse than going through this time and time again is going through it and not knowing WHY. God, there has to be an answer. There has to be a reason behind this! It's just a matter of finding someone who has that insight, and I know you've been looking everywhere already.
You know what REALLY gets me? You've had a baby before! Your body does know how to get pregnant and how to sustain a pregnancy past CD12. It's just for some reason, it's forgotten (or is being prevented) from doing it again.
I'm frustrated for you
As far as your options go, what are you thinking? I must say Option 1 is not very attractive but nor is going through this cr@p time and time again, so I'd understand if that was the road you chose.
If it were me, and I had access to the finances to allow me to do it, I'd be doing a whole fresh cycle with a new egg donor and a new sperm donor. Preferably with donors who have had successful pregnancies resulting from their donations previously. I know it's no guarantee, but I'd take some reassurance from a previous success.
Big hugs hon. I had so hoped this was The One for you. God knows you've done the hard yards.