I became gay 3 months ago how do i tell my gf that i dont love anymore?

I am 27yo my bf is 20 and he is the best partner i been with but i also have a girlfriend i been with for 6years but i dont love her any more i not married to her but i want to marry my partner reece i in love with him
Answer
Just be honest and tell the truth, thats the only sure way to sort out your problem.