IVF with transferring two embryos

Wendy

We had our consult the other day and my RE was giving us reasons as to why transferring one is better than two. I’m 41 and have had 2 miscarriages this year that could be due to two MTHFR that are treatable with methylated B vitamins. The RE also said the divorce rate is higher with twins. WTH? Because of my age, I wanted to transfer one of each sex if we produce enough eggs.

Has anyone been told why to not transfer two?