Your role is extremely hurtful and has many of the same overwhelming emotions and pain found in a betrayed spouse that is straight. Possibly, you saw it coming and thought it might go away, wait it out or you had no indication or suspicion that your partner was cheating. Often you are the last to know and possibly, your role will be more complicated if your partner cheats with a man rather than another woman.
Your situation can become more complicated in what is now your bi-sexual triangle. There is often so much hurt surrounding your lover’s affair that often paybacks become more important to you then her betrayal itself. Tempers escalate and the affair can consume your entire being. You want answers and expect details once your partner’s betrayal is no longer secretive. Often because of the closeness within the lesbian community it’s more of a challenge having your lover’s secret hidden as the gossip flows.
You had no say so nor were you consulted ahead of time. Regardless in any relationship or marriage the possibility of an intruder finding their way to your partner and maybe you is very real. You will get through this and in time get over it.