How many embryos to transfer?

Hi, everyone, I am scheduled for my FET on the 23rd of December. This is my first frozen transfer. My first ivf cycle ended in August in a miscarriage at 8 weeks with twins. I have 2 more embryos and my dr recommended to transfer both now as per frozen transfer the chances seem smaller for a pregnancy.

But as these are my last embryos I am a little scared to transfer both of them. We did not do any embryo testing as they don't do this as the clinic. I am 37, husband is 36 and we have unexplained infertility. Thank you and good luck to all!