Update: Finally made it to transfer

Ta
Transferred our sole embryo this morning. Opted to do fresh Day 3 without PGS as everything went kaput by Day 5 last cycle. Today's eggy was a 6 cell grade 2 (grade 1 being best) but with some multinucleation. I'm trying to stay cautiously hopeful for my husband's sake, but in my head, I'm thinking that it's not going to work. 
This was <a href="https://glowing.com/glow-fertility-program">IVF</a>#2 for us. We have unexplained infertility though my AMH is low. TTC#1 since August 2014. We've been able to conceive naturally without a problem (first time each time), but each time resulted in a MC (3 in a row). After the last one, we moved onto <a href="https://glowing.com/glow-fertility-program">IVF</a>.
And here I am now, hoping that this eggy makes it but trying not to set myself up for more disappointment. How do you balance optimism and rational self-protection?