Role of egg and sperm in embryo development

I have had 2 failed IVF/ICSI and 2 failed FET's. I produce quite a few good quality eggs (18+ per cycle) and we have pretty good fertilization (12/18). Our embryos do well for the first couple of days, but slow by day 3(when we've had our transfers) We've only had one embryo make it to 8 cells on d3, the rest were around 4-6. It has been suggested to us that the first few days the egg does most of the work and by day 3 the sperm kicks in and this could explain the slowing in embryo development. (dh has low morphology)

Two options have come up, and they seem quite contradictory to me:

1. monitor the embryos longer in the lab - and hopefully grow in the lab to day 5 and let mother nature to some selecting
2. transfer earlier (on day 2), because possibly the embryos would do better in vivo than in the lab.

I'm confused.

Thank you.