Help Zaba be an Agony Aunt!

Dear Zaba,

I know this is not your field of expertise but I was really hoping that you would be able to assist me even if it's with a little bit of advice.

My name is Thembi* and I am [in my 20s]*. I have been in a relationship with my boyfriend for six years now. In 2013, he was involved with a married woman and I found out and confronted him about it. I also threatened to tell the woman’s husband if he didn't stop. As far as I know he is not seeing her anymore.

Recently, he has started accusing me of cheating. He says that I am sleeping with my male friends behind his back although this is not true. I have never been unfaithful to him. Sometimes we argue about it so much that we end up breaking up.

Zaba, I really don't know what to do. I don't want to leave him but his accusations are heart-breaking.

I'm not even sure as to how to advise this woman.

A huge part of me wants to say to her you should have left him back in 2013 - but as Selena Gomez says "The heart wants what it wants".

How would you advise her? What would you say she should do?

*The letter writer's personal details have been changed to protect her identity