<human>: Summarize the given text in a few sentences.

Throw away for obvious reasons
My grammer is terrible, I'm sorry in advance

We've been together for 6 years since we where teens and since then his sister [mid 20s] has never spoken to me once. It has caused many fights between his parents, him and his sister as she has yet, to this day, give a reason why she won't speak to me. It bothered me for a long time and I just stopped  going over to his house when she was home but his parents liked me so that was good enough for me.

Up until recently.

We played around with the idea of finally moving in together since we both had full time work and could afford living together relatively comfortably and we we're sick of having to tiptoe around his sister since his parents basically gave into her childish behavior. My parents, totally fine with it. His dad, delighted! But his mum, her reaction threw me, she didn't speak to my boyfriend for a week and a half until we decided to put moving out till after Christmas.

His mother was always lovely to me and treated me like I was a daughter. She thinks we are rushing things and why would we want to live together when we can live rent free, at home, separately..

Now he's worried if we move out his mother will blame me for taking her son away and hate me like his sister seems to and his father will take our side causing a massive fight. It doesn't help matters that his parent's marriage is on the rocks and on the verge of divorce every time one of them has a drink. 

How do we approach the topic of us living together without ripping his family apart?
<bot>: Boyfriend's mother totally against us living together despite being together for 6 yrs. What can we do to avoid ww3??