That's a valid observation. We often try to observe our friends and partners to know if any of them is toxic in the relationship we have with them, but we end up forgetting that even the family relationship we have with our parents, siblings, uncles, and aunties can also be filled with toxicity.
It is common to try and get the best out of every relationship, but if our effort is being shattered by those we are in a relationship with, stepping out of it would be the best option.