Long Term Lesbian Relationship Issue

I'm Anna, a 28-year-old lesbian from Toronto, Canada and I have a question for you concerning lesbian relationships. I'd like to know why they don't last very long? I know that you've been with your partner for 15 years and I think that's AWESOME!! But in the lesbian community, relationships seem to be filled with drama, cheating girlfriends, sleeping with exes, flirting with other women's girlfriends etc.

Since straight women usually want stable, monogamous relationships with men, I thought that lesbian women would want the same thing with other women. I was under the impression that gay men were the unstable ones and lesbians were into long-term commitment but as strange as it sounds, I'm now seeing more gay men in long-term relationships than lesbians.

Can lesbian relationships really last or am I wasting my time?