Boundaries are a hot topic in the mental health world nowadays.
Typically, we see people say that you have the right to set any boundaries you want and people should honor and respect them (which they should and hopefully will!).
BUT in reality, even if they're willing to honor your boundaries, people are allowed to have their own reaction to them.
They are allowed to be upset or angry with the boundary that you are putting in to place.
The fear of this happening isn't a reason to dishonor yourself and allow behavior or treatment to continue that you are not comfortable with.
It's important to realize that It's unrealistic (at best) and selfish (at worst) to assume that just because you set a boundary that everyone will not only honor it but also be totally fine with it.
It won't be all rainbows and butterflies. Sometimes, they will more than likely be disappointed.
But knowing this ahead of time can make it easier to hold strong on the boundaries that mean the most to you (like going no-contact with an ex temporarily even if they aren't happy about it!).
Like I always say, everything is co-constructed! Understanding both sides make it easier to navigate