Take a look at the sentence again:
When Simone and her husband discovered sixteen jars full of insects in their
daughter's room, they decided to get Maria a dog, tolerating
one four-legged animal seemed
better than having fifty six-legged "pets" in the house.
Tolerating one four-legged animal is the subject for the verb seemed. You hardly ever use a comma to separate a subject from its verb.
Go back to the sentence to try again.