AITA for not accepting my sister’s relationship with my ex despite her having cancer as a teenager?

A Reddit user shared their experience of betrayal after discovering their sister, who had cancer as a teenager, is now in a relationship with the user’s ex-boyfriend. The user’s family is pressuring them to accept the relationship, citing the sister’s past health struggles as a reason for her actions, while the user feels deeply hurt by the situation. To dive deeper into the complexities of this family conflict, read the full story below…

‘ AITA for not accepting my sister’s relationship with my ex despite her having cancer as a teenager?’

My (25F) father married my step-sister’s (23F) mother when I was 4 and she was 3. We’ve lived together most of our lives and are a family. She and I were extremely close. She developed cancer when she was 14 and was sick for about 2 years. She’s since made a full recovery.

During that time, my parents became understandably over-protective. They also asked a lot of me. I quit my extracurriculars so I could get a job (the money went towards her medical bills) and so I could drive her to appointments. I didn’t go to dances and any fun activities I did needed to include her.

I did almost all of this willingly, the exception being having to quit my high school volleyball team – I did throw a bit of a tantrum about that, but was swiftly punished. And I think having one emotional breakdown was pretty chill given the circumstances. Anyhow, I go to college and meet my ex, we’ll call him Ben, when I’m a junior.

We fall in love, blah blah blah. He and I move in together when we graduate, so we’ve been living together for about 3 years. We were serious until July when I walked into my bedroom and saw him f**king my sister. I broke it off, tears were shed, he moved out, etc. My sister apologized at first but then backed off.

I thought she was giving me space but last week she called and asked if we could meet up. She told me that she and Ben were in love and were just telling me as a courtesy before they started posting photos online. Distraught, I left her in the restaurant by herself and did not pay my portion of the bill.

She later venmo’ed me asking for the money. She told my parents who then called me to their house, telling me how disappointed in me they are for not supporting my sister’s relationship with Ben. They brought up the fact that because she had cancer as a teenager,

she never learned proper social etiquette, and has a hard time meeting people. I don’t buy this, in part because I’ve seen her socialize just fine and since we spent a good chunk of the time she was sick together, that would also mean that I should have bad social skills as well, by that logic.

They then told me that if I don’t accept my sister and Ben’s relationship, they may have to go no contact with me. I reminded them that I’m also their daughter and they should understand my point of view, but they are adamant that this is about me being jealous of her.

For the record: I’m not jealous of her. I’m not upset that Ben picked her over me. I’m sad about the end of the relationship and do feel betrayed, but lord knows that I don’t want to be with a c**ater. What I’m upset about is the fact that my sister chose Ben over me.

That she slept with Ben knowing he and I were in a long-term, committed relationship, and continues to be with him knowing how much it hurts me. Now no one in my immediate family is talking to me and I’m getting messages from aunts and uncles and cousins telling me that I’m an a**hole and a selfish b**ch.. ​. ​

Check out how the community responded:

drb1tchcraft −  NTA. I had cancer as a teenager. I’ve managed to not have s** with either of my siblings partners, weirdly enough.

Fritemare −  NTA. Having cancer as a teenager is not a valid excuse to be a s**tty person for the rest of your life.

Rtarara −  NTA: Oh heck no! Your sister is using an illness she had a decade ago as an excuse to sleep with your boyfriend and gave that be okay. It’s not. The fact your parents are going along with this smacks of having a golden child. I’m sorry to say that sometimes the trash takes itself out. Your sister is awful.

You parents are and WERE awful (it was not your job to quit every activity to pay your sister’s medical bills and drive her around). It’s good that you know this now and can get some therapy and move on with your life. You deserve better people in your corner and they are out there waiting for you.

Papfan1 −  NTA. Her lack of social etiquette is due to their lack of parenting, not cancer. You are better off without these people. ETA: her asking you to a restaurant to deliver bad news and then requesting money for it is ridiculous. She sucks.

[Reddit User] −  So getting cancer means you can be an a**hole ? Learn something knew everyday…. NTA, obviously. Your sister is an a**hole but your parents are even bigger assholes for thinking you just need to get over it and accept things. You may not see it that way but she did you a favor because now you’re not with a c**ater,

and you know that your sister and your parents are toxic and selfish and that you shouldn’t be having a relationship with those people. They’ve screwed you over you entiere life. You’ve sacrified most of your childhood for that girl and that’s the thanks you get. They are so not worth your time or your awesomeness.. Just f**k them!

Steups13 −  NTA at all. She wanted you to venmo her money? Damn! You already venmo’d a bf to her. She’s a sad, greedy, jealous individual who uses her illness to excuse her bad behaviour. If you take her cancer out of the equation, then it’s likely no one in the family would talk to her.

Having cancer does not give her a get out of jail free card! It is not an excuse for betraying you. She is a mahoosive ah.. Edit: spelling

fuzzy_mic −  NTA – What your sister learned from the cancer is that your parents will b**ly you into catering to her. (Quit volleyball because she can’t play ?!?) Yes, that impacted her social skills.

[Reddit User] −  NTA NO NO NO HELL NO!! Did you tell your parents the way they broke it to you was by F**KING IN YOUR ROOM!!??? If they said “hey sorry we’re in love I’m so sorry!” That’s one thing but going behind your back and f**king for who knows how long is DISGUSTING. Neither of them deserve any respect or forgiveness they do not care about you and never have.

wolveschaos −  NTA. You’re 25, go NC and live your life to the fullest. Don’t let people who couldn’t see the betrayal done to you, into your life. Her being a cancer survivor has absolutely nothing to do with anything that’s happened.