Discomfort does not automatically mean the boundary is wrong
If your family has always expected quick replies, unlimited availability, or agreement, a new limit may feel like you are breaking an important rule. The guilt can be real even when the boundary is reasonable.
Try asking what the guilt is responding to. Is there actual harm to repair, or are you feeling the strain of behaving differently from what people expect?
A boundary describes what you will do
Boundaries are often clearest when they focus on your participation: when you will answer, what topics you will discuss, or when you will leave a conversation. They do not require the other person to agree that the limit is fair.
Keeping the message brief can prevent the boundary from turning into a debate. You can care about someone and still decide what contact is workable for you.
Give the new pattern time to become familiar
The first attempt may feel awkward, and family members may test whether the old pattern is returning. Repetition matters more than delivering the perfect explanation.
Individual counselling can help you prepare for the emotional aftermath, notice when guilt becomes over-responsibility, and choose a boundary you can realistically maintain.