dwell on (someone's) faults

Translations
зацикливаться на (чьих-либо) недостатках
It's not healthy to dwell on someone's faults in a relationship.
Не полезно зацикливаться на чьих-либо недостатках в отношениях.
Definitions
To repeatedly think about, emphasize, or focus on someone's mistakes, shortcomings, or negative qualities, often in a way that is critical or unhelpful.
Words
dwell

verb
зацикливаться
on

preposition
на
someone

pronoun
кого-либо
s
чьи-либо
faults

noun
недостатки