That's the reason why nobody wants to be married to me.
I don't know any other way to earn my bread and butter. That's why.
ご質問ありがとうございます。
① "That's why I still can't get married."＝「だから未だに僕は結婚できないんだ。」
② "That's the reason why nobody wants to be married to me."＝「誰も僕と結婚したくない理由はそれさ。」
③ "I don't know any other way to earn my bread and butter. "＝「それ以外食べていく方法を知らない。」
"That's why."＝「だからさ。」
ご参考に。
アメリカ合衆国 
