Woman wants to confront adult stepdaughter; 'Her behavior is TOO NASTY TO IGNORE.' AITA?

When this woman is fed up with her adult stepsister, she asks the internet:

"WIBTA if I tell my diagnosed bipolar adult stepdaughter how nasty her behavior towards me is?"

I (30f) live with my boyfriend (48m)of 5 years and his daughter who is the same age as I am let's call her Amy. Amy is very socially awkward and inexperienced, she's more like a 16 yr old mentally so our relationship is more like I'm the older sister/mentorish.

I've helped her come out of her shell, get out of the house, encourage her to try new things and set goals for herself (since if it were up to her father she'd be a jobless virgin and stay in the house forever).

I've even helped her reach some of those goals so far. I buy her things, take her shopping and cook dinner 5 times a week for the both of them. I love her a lot and in my eyes she is a dependent but also a friend.

Over the past 3 yrs of living together as a family we have great moments but then she has her moments of mania and her disrespect seems directly targeted at me. She will randomly blatantly avoid or ignore me and treat me as though I'm invisible yet speak to and be warm with her father.

Each time she gets like this I get the feeling that I am being used for my resources and she doesn't really like me or would rather me be gone. She's gone as long as over a month without speaking to me and rn it's going on 3 wks. I am generally not the type to take disrespect lightly but I have been biting my tongue for the sake my relationship.

If it weren't because of him, I would've said f her a long time ago. My bf would usually have chats with her when she comes out of her mania state about it but I haven't seen that make an overall change and it's gotten to the point that it's causing us to argue. I know it's putting him in an uncomfortable situation.

I'm tired of her treating me so badly when I'm so kind and nice. I'm tired of being nice. WIBTA if I told her how I actually feel (when she's out of mania) and let her know that that is the last time she will do this to me and to continue not speaking to me anymore?

Let's see what readers thought:

phiv writes:

YTA. First off, the way you talk about her is super condescending, which probably comes across in how you interact with her.

In her good periods she's probably able to ignore this and try to maintain a relationship with you for her father's sake, but when she's in her low periods it's probably too much effort for her to deal with you.

She's also much more comfortable with her dad, since she's known him since the day she was born, so she doesn't feel the need to put on a show around him.

Second, it sounds like you're putting no effort whatsoever into understanding her illness. You expect her to just magically fix her bipolar disorder for you, but you're not willing to make any changes at all to treat her with any kindness while it's having a profoundly negative effect on her life.

She's not "being disrespectful to you" - she's having a depressive episode. What you're interpreting as "ignoring you" may actually just be her being nonverbal towards you. It happens.

Maybe stop treating her like a fg child, first of all, secondly try educating yourself about her illness, and third, stop making it all about you. It's not.

mayoghw writes:

I wouldn’t address anything when she’s in a period of mania. When she’s relating to you in a more controlled state, discuss her abusive behavior toward you and ask how the two of you can handle it better.

Additionally, if she is continually cycling so rapidly (4 weeks on and off) it’s time to discuss changing or starting meds. Unfortunately she may target you for her abuse because she feels safe doing so. But that doesn’t mean it’s right. NAH. Bipolar is a disease.

faet writes:

ESH. I can’t believe she’s cooking and cleaning for a man 20 years her senior and his daughter the same age.

I’d need to shower after every conversation with people like that. She’s the asshole to the daughter for treating her bipolar in this way, and an asshole to herself for allowing her 50 year old boyfriend and his adult daughter to treat her this way.

marajade2 writes:

NTA. I was diagnosed with Bipolar disorder 2. I know that my attitude can be hurtful and my actions cause people grief. I do my best to ameliorate my behavior and if I mess up, I apologize and try to do better.

Being mentally ill is terrible (I'm currently in a depressive state and not doing well) and it affects our lives and behavior, but it's not excuse to be nasty to others.

managerlimp writes:

NTA. Mental illness is not a catch-all excuse for crappy behavior.