Should i still marry him even if i feel this way?

I was born in west africa. Over there it is traditional that your family picks your bride/groom. About 2 years ago i went to stay with my family over there for about a year. While on my stay there i met a guy who was in the same " tribe" as me. At first we didn't like eachother but soon began to get alone then fall in love. The only problem with our relationship is that he was already given a bride. Although they didn't get along at all, the family refused to undo the engagment. The bride that he was given was my cousin and she's like a sister to me. After a year in africa i came back home where me and the guy still communicated. As time progressed i began to fall more and more in love with him. After months of begging his family undid the engagment and now we're engaged. My cousin was not given another groom. Although i love gim very much, i feel as if i'm his family's second choice. They missed the first time and i was the only one left. Would it be wrong for me to marry him knowing that my cousin was regeted. Sometimes i feel as if he only wants to marry me because he's mad at his family for choosing his bride. Please only serious answers, this is an important matter. Should i marry him knowing that all of the above will hang over my head for the rest of my life? Is the guilt really worth marrying the man i love?