If it were not for his aspendicitis〜はおかしいですよね。If it were not for〜は、「〜があるおかげで、〜に感謝して」のニュアンスがあると思うので、If it were not for his help〜みたいな文脈なら使えそうなんですが、どうでしょう？
I would consider marrying him if he didn't waste so much money shopping all the time.
If it were not for ... で「もし…がなければ」という意味なので、これを使って言うこともできますよ。
ーIf it were not for his bad shopping habit, I would marry him.
「彼の悪い買い物癖がなかれば、彼と結婚するのに」
ですが、この言い方はちょっとかたいので、次のように言うともっと自然です。
ーI would consider marrying him if he didn't waste so much money shopping all the time.
「しょっちゅう買い物して大金を無駄にしなければ、彼との結婚も考えるのに」
ご参考まで！
カナダ 
