My Husband Is Not Ready To Stop Cheating On Me - Woman Laments

We met in school during my pre-degree and dated for 7 years before he proposed to me. Before the proposal, both our parents had been pestering us to get married and start having children.
 
We started trying 6months prior, and 6 months after proposing I got pregnant. Few months later we did our introduction and got married (registry) March this year.
 
About two years ago, he met a lady where he was supplying his goods.
 
According to him, the lady has been doing everything in her power to push his business. Every time I suspect there was more to their friendship, he always assured me there was nothing, that she's just a friend. sometimes he would even travel with her to Abuja to sell his goods which I had to allow since it was helping his business.
 
8 months into my pregnancy I noticed a drastic change like coming home very late, he hardly eats at home, he barely talks to me, he's always on his phone. I knew something was wrong and every time I talk to him, he always assured me that everything was fine.
 
After the delivery and naming of my baby I expected things to go back to the way it was, but it became worse. he changes his phone password almost everyday and still hides his phones from me.
 
One day I cried and begged him to tell me what was going on, after hours of begging, the first question he asked me was "where was it written in the bible that marriage has to be between one man and one woman and not with different women", "why can't a man marry two or more wives if he has the resources to take care of them equally"(the lady is a muslim btw).
 
He confessed that he has been dating this lady for over two years and has no plan of leaving her, and theres a possibility he's going to marry her. I'm just 26years with a one month old baby, I didn't sign up for this.
 
While growing up, my mum has always warned us against polygamy.
 
Although he's promised to be there for me and still wants our marriage to continue, but the thought of my husband being with someone else is killing me. I've tried to reason with him several times but I end up hurting even more. I've been praying but still no change. He's been trying to compensate with gifts and money but thats not what I want. he doesn't want me to tell anyone and I feel reporting him to his family will even worsen the case. We've always settled our issues ourselves without involving anyone. I've tried everything I can just to take my mind off it. I need someone to talk to, prolly a friend or a counsellor. I've been crying for days now, I've not been eating well and I have to Bosom feed my child. I never knew my life would be this complicated. I don't know why he got married to me if he already had this in mind. I hate my life right now.