。
She's always nitpicking at her husband.
Literal
She [topic-は] constantly husband [genitive-の] fault-finding [nothing-but-ばかり] is-doing.
A vivid complaint sentence. しょっちゅう ('constantly, all the time') and ~ばかりしている ('does nothing but X') both push the same idea, doubling the impatient tone — the speaker is clearly tired of watching this behavior. あら探し (literally 'hunting for flaws') is the noun for picky fault-finding; あら ('flaw, defect') originally referred to the rough, undesired bits in cooked rice. The compound 夫のあら探し ('husband-fault-finding') is structurally interpretable two ways in English, but here the husband is the target, not the agent: 'fault-finding aimed at the husband.' Context — and the 彼女は topic — pin down who's doing the looking and who's being scrutinized.