Transfer 1 or 2?

Crystal • 4 failed IUIs before Fresh IVF cycle July 2016 which resulted in my 3 year old daughter. FET Jan 2018 resulted in miscarriage. August FET #2 & October #3 & January #4 failed. Round 2 of IVF June 2019 failed. Surprise natural BFP Nov 2019🤞

So I had a successful fresh cycle in 2016 which resulted in my 2.5 year old. I've been trying for #2 with FETs all year with no success. First ended in miscarriage at 6 weeks and the next 2 failed. Everything always looked great...perfect embryos, lining and bloodwork. I have 2 embryos left, a early blast and 3BB. RE is willing to transfer them both but I'm torn. I really want it to work obviously but also do NOT want twins. I'm not sure I'm willing to go through retrieval again so these are more then likely the last 2. What would you do? TIA