So my sister, let's call her K (19), has been dating this young man, let's call him N (19), for almost 2 years now. They have been great friends since middle School, but he always wanted more from her. Even when she was in other relationships, although he never once acted on it or pressured her to leave her at-the-time boyfriends. I was always secretly rooting for him.

Time jump to their senior year of highschool, she gets out of a terrible relationship, bounces around a couple guys, falls into a very deep depression and only continues to rely on "boyfriends" for emotional stability. N is by her side as the best supportive friend he can be. After a few rounds in hospitals and seeking mental care, they decide to become a couple. She is doing great, but obviously still has moments of emotional instability and depression.  In fall of her senior year she decides to move out of our parents' house because "they are crazy and controlling". She had just turned 18 and had convinced herself and her friends and friends' parents my parents were crazy and not allowing her to be an adult. They only had 2 rules, don't get drunk and don't smoke in the house. Other that those 2 things, she was free as a bird now that she was 18. After a lot of emotional trauma for the whole family, she moves in with N, now her boyfriend of 3 months.

Fast forward to about 6 months living with N and his mom and stepdad. We are seeing very serious signs of emotional abuse and she eventually tells us of physical abuse as well. Not only this, but her depression has been even more extreme and she has frequent panic attacks, almost all with N being the cause of  stress. After  6 months of us telling her we will do anything to get her out and basically telling her she needs to leave him and she can live with either parent or myself, she decides to finally do what she needs to be better. She moves out of his house, breaks up with him and moves in with me (I have my own house about an hour away). She does all of this over one weekend, after deciding it is what's best for her.

Fast forward to 1 month later, after sitting on my couch for 2 weeks without a job, my parents buying her a car, all new furniture for her room, she decided she needed to give N a second chance. K also now denied all accounts of any emotional or physical abuse from N. K texted my family in a group text and basically demanded we accept her choice and tell her we love her, or she won't talk to us or be in our lives anymore. And this is something she would follow through with as she has shut some of us out for months at a time before.

Now, currently a month after K got back together with N, all of her stuff is still at my house, but she has been living with him and his mom and stepdad while she waits to find her own place. K did decide she shouldn't live with N anymore, but that they should still be in a relationship.  

Now she is asking me to let N come with her to my house and hang out and help her pack to move back. So, am I the asshole for not wanting to have anything to do with N?