Multiple avenues: They told me multiple times in different ways that their other partner was their best friend and the person they were closest to, this partner knew about our relationship bumps, but I didn't know anything sensitive about them in return, the person cancelled time together to keep spending time with other partner, they broke an agreement, lied about why the agreement was broken, and lastly shared some of my most vulnerable personal information with them without my consent.
Yeah, I wouldn't accept any of this.
Then there are the things that aren't technically unethical but sting on top of what was mentioned above -- like prioritizing time and giving more time to the other partner rather than me. I know anyone can decide what time and capacity they want to give to another person, and there is no "fair," but sometimes when there is a clear imbalance it *really* hurts.
My boyfriend Aries has made the decision (from his heart) that I am his primary, and he informs anyone else he tries to date that this is the case upfront. He tells them we spend our weekends together, so new partners may not get much, if any, weekend time. He does usually spend part of one weekend a month on other partners or platonic friends, after checking in with me, but he just really likes to be with me from Friday evening through Sunday evening the majority of the time.
Therefore, you could call his attitude hierarchical. He is best suited to other partners who can do midweek dates, after work, or who only want to see him once a month on a Sunday afternoon/evening.
My other partner Pixi is my nesting partner, but she spends half her week "nesting" at her bf's house too. So, she has two "primaries," Malachi and me, and I have two "primaries," Pixi and Aries.
In your case, was your bf upfront that he had a primary, with whom he lives or spends most of his free time, and therefore would only have X days/hours a week free for you? Did you agree to this? If you were aware and agreed to it, then it's on you to ask to renegotiate that now, if it no longer suits you. Maybe you thought he'd just naturally want to, and be able to, spend more time with you after a certain amount of time, but he's still content with the original agreement.