People on this thread tend to be long on opinion and short on data. Demographically lesbians have relationships similar in duration to that of heterosexuals and tend highly towards monogamy. This is to be expected since in general women tend to prefer stable monogamous relationships.
I think you are right about lesbian relationships lasting longer than gay mens’ but it still doesn’t make it right. There is more domestic abuse in lesbian relationships than the normal average. Women tend to be very jealous not only of other women but the fear that they are going to lose their partner to a man so its a double whammy.