"i was told that monogamous relationships are abusive because they established a slave like ownership over you partner"
But wait, lots of people happily engage in relationships that involve slave-like ownership in the BDSM community and these aren't considered abusive for one reason -- informed and enthusiastic consent. Same deal with monogamy!
I'm being somewhat tongue in cheek, because of course I don't consider asking your partner not to sleep with anyone else to be a remotely "slave-like" situation (that just seems so absurd), but the same standard does in fact apply -- if both partners are enthusiastically consenting to monogamy then it's hardly abusive, is it. Of course if one partner is NOT happy about being monogamous, well, that could potentially be considered unhealthy or even dysfunctional, but I still would never consider one partner making a simple request of another about the way they do or don't share their body with others to be abusive.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.