Was with gf for 11 yrs,we split up and a month later my best friend of 25 yrs confessed his love for her. He knew I wanted back with her but 7mths after they started f*$@ing. I did not find out till 1.5 yrs after they stopped! ????
you have no choice but to accept whats happening... you may or may not forgive her...
she seems to have moved on..
So what is your question? Are you trying to get back with her? Or do you issues with your best friend?