Boyfriend forced to marry his cousin...

My boyfriend and I were together for about two years. Until one day came, after his recent visit to Afghanistan... That he announced he is engaged to his cousin. In the beginning he said he loves me and wants to marry me. And I entered this relationship knowing that he'll marry, because that's what he promised. He said, I have to agree otherwise it will be a sin to be in a relationship. And no, we haven't done anything sinful. Anyhow, he says he liked that I was talented and interesting. He wants to have well educated children, and thinks I'll be the perfect mother to his children. And he believes both of us can make each other very happy. At first, I thought he was mad. But slowly I warmed up to him and accepted his proposal. Because he is very calm, sweet, gentle and soft. He is also a very responsible and dependable type of person and very caring towards his family. That's why, he struck me as a family man. But most of all, he seem like the type of guy who has deen and imaan. And I like these qualities in a man. So we planned to get married after graduating from University.

Second of all, my mom, sister, cousin and khala knows about him but they don't have much problem with it. He also told his mother and sisters about us and they liked me. His family lives in Afghanistan btw. And when I'm around and he talks to his mom on the phone, she even acknowledges me and sends me salam. Obviously, I also give her salam. Anyhow, he was so sure that he could convince his father too....

However, my life got shattered when I found out he got engaged. We had our entire life planned out, like we will travel the World and everything.. Sharing our hopes and dreams.. But, he was already betrothed 7 years ago!!! And he cannot break it! Because it will create family problem and destroy his cousin's reputation. He said he was unaware of his betrothal, because it was an agreement within family and he didn't give it importance before. But now, he was forced by his parents to get officially engaged. His father is extremely strict and my bf once hinted him that he would rather marry a foreign girl, but his father got mad and threatened to disown him. So he didn't tell him about me.. Instead, his mother advises he should marry both me and his cousin!

Now he says, it's not his fault since he was never given the choice. And he doesn't want to disappoint his family nor does he want to lose me. So he's been trying to convince me to be his second wife! And the fact that he's marrying his cousin for his family, but wants to marry me because he loves me and I am his personal choice. He says, he can keep his cousin in Afghanistan with his family. While, he'll live with me in Canada, but he has to go to Afghanistan every year for 2-3 months for his family. He once even said that maybe he will begin to love his cousin. So we've been having lots of fights and disagreements. Because I don't want to share him, nor do I want him to be away from me for so long. He scolds me for being so selfish and wants me to think of HER like a sister.

But, I can't! I am that sort of girl who still plays Nintendo like Pokemon, really into Classic Rock, period dramas and a literal bookworm. So, I never expected myself to be in this sort of situation! I am a very idealistic type of person and my idea of relationship is that love is made for two! And I cannot bear to think there will always be another woman between us. I am Bengali Muslim btw, and our society isn't backward like that, but polygamous marriages used to happen during my grandfather's time, not now! And if I marry him, then I can never share my short comings or problem about this to my family. Because my family loves me too much and they don't have such low expectation of me. Even my family would need enough convincing that I want to marry an Afghan guy... So talking about being second wife is out of the question!

Ever since knowing about his engagement, we have been alternating between relationship mode and breakup mode. Still, I love him too much and I relent but then again I refuse to accept it! I am very conflicted about this situation! What should I do!!??? Please, help me! I don't have any kind of idea or experience about this! And I cannot share such shameful thing to anyone! Advise me!!