Sister to My wife always come to fight me anytime I have Problems with My wife, what Should I Do?

In some many occasions, elder sister of my wife has come to fight for her sister anytime I have problems with her.

The problems sometimes which is always cause by her.

Their was time when we had our second baby so she is the one staying with us while taken care of her sister and the new born baby, and issues come up about generators.

So when my wife started saying some aggressive words and get angry, instead of her sister to settled both of us, she join her sister to fight me.

Their so many case like that I didn’t want to mentioned here.

Another, is we had an issues so called her mother to report to her, the same elder hijacked her mother phone and warn me never to call her mother again, she and my wife accuse me of insulting their mother.

But when I stop calling her they get worried said am maltreating their sister.

Recently my wife accused of having an affairs with a lady I employed to work with me in office, so confronted her she said it someone that told her.

According to her, the person which happen to be a son to another of her elder sister told her that I ask the girl out, and I even promise to rent house for the girl.

So what I have do is to call the girl, take her to my wife shop and ask her in her present.

She denied the allegation, we later found that the son is leing.

Despite the truth has come out, the same sister and the son that lie join hand together to quarrel me.

Now is the marriage worth staying?