/cheat

My gf for 7 yrs got attached to her old friend after flirting with her. She confessed she fell "sparks" and even met once where they hugged each other, but still wanted to be with me. She mentioned she stopped that 1 week before confession with me and that incident made her realized that I'm the right person for her. Their communication lasted for 3 months which is during our rough patch.

God knows I love her. Should I stay? How can I forgive and forget her?