To make it parallel I would say to put it in this format: We can’t go back; to go forward is our only option. This makes the verbs the same.
The theme of the oval portrait is Fatal love, the wife in the story loves an artist but he loves his art. so by the time he was done it happened that she had died by his side.
Using the vowel with no other markings.
Try swimming and maybe an idea will pop up, wish u luck!