It was based on an autobiography so there's only so much you can do about that.
what? that's completely untrue. like, the gay boyfriend thing, okay, there's no way to really play that without going for a laugh, it would be trite, but it's also a kind of stupid story to begin with. then the cheating dude is just SO OBVIOUS because for ten minutes we're given all these scenes of how happy they were and of course it's going to come crashing down.
you shouldn't excuse real life situations being played as cliches. I've read Persepolis, and maybe the change in media added it or I don't remember it well but I don't remember it being so predictable.