I was too dependent on him, that’s why it didn’t work out.
I was too dependent on him, that’s why he broke up with me.
I was too dependent on him．これはつまり、彼に頼りすぎた、または頼りすぎて自分一人では何も出来なくなった、という意味です。
❶I was too dependent on him, that’s why it didn’t work out.
(彼に頼りすぎた、だから上手くいかなくなった)。
❷I was too dependent on him, that’s why he broke up with me.
(彼に頼りすぎた、だから別れを切り出された)。
〜と言えます。
I was obsessed with him, that is why it did not go well.
I was obsessed with him, that is why it did not succeed.
「依存する」は英語で "obsessed" 、「上手くいかない」は英語で "does not go well" または "does not succeed （成功しない）”と言います。なので、
「彼に依存していたから（関係が）上手くいかなかった。」は英語で
1. "I was obsessed with him, that is why it did not go well."
2. "I was obsessed with him, that is why it did not succeed."
と二つの言い方があります。
ご参考になれば幸いです。
アメリカ合衆国 
日本 
