投稿された例文は、既に存在するため追加されませんでした。
The implications of the そうじゃなくても are totally missing from the original English version. Adding a replacement.
Perhaps "even though" would be better than "even if."
I'm not sure, though, it was just my first gut-feeling.
Perhaps the following is a little more natural-sounding.
Even though he isn't a good husband now, he'll become one in the future.
Maybe, even,
Even though I'm not a ...., I'll ....
