This is exactly it. My partner's former bandmate had a girlfriend that would do the same thing - the band would tour abroad, and this girl would tell him that it was okay to hook up with other girls, and play like she was super chill about it, but would then be very obviously upset that it would happen. They had a very unhealthy dynamic - she was insecure but desperate to seem like the "cool girlfriend," and he was fully aware of her insecurity but probably would have fucked around on her anyway (which they both knew) so it was convenient for him to be like, "But she said it was okay," when it obviously wasn't. I doubt I even need to say it, but: obviously, they ended up breaking up, and feelings were hurt all around.

If you're doing something you know will hurt your partner, you probably shouldn't do that thing. Or, if doing that thing is more appealing than being with your partner, you probably just shouldn't be with them.