You may or may not have heard the term before, but if you practice non-monogamy/polyamory, or have a partner that does - you have probably probably come across a partner that has expected it or have been the partner to expect it.
What it is:
Veto Power is when you give your partner the power to end your other relationships. It can show up in many ways, such as when you both agree to it (I am okay with you dating other people, but if our relationship starts to struggle you will have to stop dating them, and focus on us.)
It can also show up covertly, such as when your partner has hard feelings about your relationship with them/the other person - and tells you they want you to end your other relationship, and if you don't then they will change the dynamic of yours. It can also look like stonewalling you or being angry with you every time you spend time with your other partners.
Veto Power creates an imbalanced dynamic where the other partners are not fully in control of the relationship that they are in. Unless otherwise agreed upon by all parties (such as the other partner being okay with the veto power), it creates an obstacle of feeling in control of the direction of their relationship.
What do you think, do you think that veto power is necessary?