Once bitten, twice shy?
What do dogs do? Well quite a few things, like bark but a bad dog may bite
Bite, bit, bitten
If you have been bitten, the next time you see a dog, you might be more cautious
Shy, usually means coy or unconfident with people, particularly of the opposite sex
In this idiom, it means weary
Once bitten, twice shy is often used to describe being cautious after an unfavourable experience, including a relationship
Here's a song by the same title and some big hair, seveties glam rock - babe!