1. The Valonqar is NOT JAIME LANNISTER

The theory states: 

“When your tears have drowned you, the valonqar shall wrap his hands about your pale white throat and choke the life from you.” 

Jaime has only one hand so he cannot wrap his HANDS around anyone’s throat. Also the only reason for Cersei to cry real tears now is if Jaime dies. So if he is dead he cannot be the Valonqar.

2. Who Will ...