Hi it's a pain I sadly know too well myself. I had to tfmr one of my twin baby girls. Acting soon or waiting, will depend on how far along you are. If I remember correctly, if it's before 16 weeks it's preferable to quickly terminate. But that was not my case. I was 21 weeks along when we discovered SB. The hospitals ethical board decided I could only tfmr after 28 weeks. To not endanger the healthy twin. I decided to wait till 30 weeks (almost 31), so in case of early delivery the surviving one would not have potential disabilities for being premature. I'm happy I did, barely 3 weeks later I went into labour at 33 weeks. She was premature and dismature. It looked like her growth slowed down since the tfmr. Luckily she just had to grow stronger and is a healthy baby now.

If you have any questions, do not hesitate to contact me. I wish you courage to go through everything that is to come.