An apology is pretty worthless if there is no commitment to stopping or correcting the behavior that's being apologized for. I see no reason why you should expect this person (let's call her "she"; "they" is so awkward.) to consider that she will change her behavior based solely upon "I'm sorry."
The way I see it, your best bet is to accept her, exactly as she is: a person who expresses lots of negative thoughts. Also, accept yourself exactly as you are: a person who absorbs her negativity and makes it his own. Once you accept the reality of that, and that she's not likely to change her behavior just because you want her to, then see what your next right action is, letting go of any need for her to change.
For instance, if it were me, I might tell her, "Look, Brunhilda, I understand that you are sorry for your habitual way of being and the impact it has on me. I can see that it causes you pain that your continual negativity leaves me feeling stressed out and not wanting to be around you. And I've noticed that you don't seem to have any intention to change that behavior, or to make any commitment to me to be positive around me. And my best choice in really leading a joyful life is to surround myself with people who are committed to thinking thoughts that feel good when they think them. I would really love for you to be one of those people, and I request that you think about whether or not spending time with me is important enough to you to intend and commit to being a positive force in the world. If you don't want to, that's fine; you are absolutely perfect exactly the way you are, and I still love you and wish the best for you -- but for my own well-being, I would choose to limit our time together. That sounds like an ultimatum, and I'm sorry if you feel pressured -- I am totally open to exploring a third, unknown solution with you, too, because you mean a lot to me. What do you think we could do so that we're both satisfied?"
You probably don't talk like that, but you get the gist of what I'm saying, right? Don't make her wrong, grant her the freedom to be exactly who she is and exactly who she is not, and make your well-being your number one priority, while generating love in the conversation.  |