I know my partner should consent if i want to date other people, and he does enthusiastically… but what if he doesn’t agree with the person im seeing because he doesn’t like them? Should my partner get a say in who i date?
This is a really thorny issue, and different poly people have different arrangements about. Some people prefer a “veto policy,” where their partner can ask them not to see someone that they find obnoxious or unpleasant. Other people have zero tolerance for a partner’s attempts to “veto” their partners. This often relates to whether there is a “primary” partnership that supersedes others, or whether all relationships are managed on their own terms.
As with most things, there needs to be a balance, and open communication, and compromise on both parts. If your partner just doesn’t like someone, they can try and be scarce when that person is around, or try to find some common conversational ground, or suggest that you gently ask your partner to try and be less pretentious, more polite, etc. But you two need to decide whether one person dating someone your partner doesn’t like is a dealbreaker, or not being allowed to freely choose partners is a dealbreaker.
If your partner thinks someone is toxic, abusive, or actively unhealthy, if they’re making you so miserable or manipulating you such that your other relationships are suffering, then I’d say they have a right to walk away. But no one can “force” another person to do something - their choice is whether to stay with you, not whether to demand that you leave the other person.
I think of it this way: my partners can’t command my behavior, and I would be very upset if they tried. If they hate the smell of lotion, they can’t say “I forbid you from wearing lotion.” They can let me know that it bothers them, and ask if I’d be willing to stop, and I can choose to honor that, or decide that I need to wear lotion and they need to deal. Then they can decide whether being with a lotiony person is tolerable for them, or not.
When it comes to relationships and feelings, there is no “should” - I can’t give you some supreme dictate for how you and your partner are allowed to manage your relationships. It’s up to you two to find balance and openness and to both clearly understand and agree to the terms of your relationship.