I regret ever allowing my younger sister stay in my Matrimonial Home, Lady Weeps

This is her story;

I regret allowing my younger sister to come live In my home.

I got married just six months ago and not too long my sister asked If she could come live with us. My husband said she Is family I can allow her.

My job entails travelling for two week to get goods,so at times I travel for two weeks and live my husband with my junior sister.

Several times I have heard from people In the environment that my sister and husband have been going out. But I don’t listen to outsiders because I believe believing outsider before your family could scatter my home.

So I decided to ignore, one fateful day I came In late and my husband had slept,he dropped his phone carelessly and I picked It up,while going upstairs to the room a text message came In and It was my sister who messaged him.

I was curious as to why she would be texting him at such hour, I read the message lo and behold the content was I am pregnant for you.

She said she was six weeks gone. I was shocked but I kept quiet. I told my mum and my mum told me she would ask her probably she and my husband were trying to prank me.

But I told my mum that It Is not so.
Our family head called a meeting and asked her why It Is my husband of all people that she Is Interested In,though my husband was Insulted as well but because this Is an Issue between sisters his own was little.

My sister said the reason why It had to be my husband was because all the things happen to me,she said everything works out fine for me and she Is envious of me.

I need advice please,It Is a thing of shame and disgrace that two sisters are pregnant for the same man.
Because I am pregnant as well.

Should I terminate my pregnancy and allow my sister continue with him or what should I do?
.also please was I wrong to have accepted my junior sister Into my home?