Ata' al-Khurasani (may Allah have mercy on him) said: I asked Sa'id bin al-Musayyab (may Allah have mercy on him) about ila. Then I passed by Abu Salamah bin Abd al-Rahman (may Allah have mercy on him), and he asked: What did you ask about? I said: About ila. Abu Salamah (may Allah have mercy on him) said: Shall I not tell you what Sayyiduna Uthman and Sayyiduna Zayd (may Allah be pleased with them both) used to say about it? They used to say: When four months pass, it is one divorce.
This is not mahfuz (preserved); Ata' al-Khurasani is not strong, and what is well known from Uthman (may Allah be pleased with him) is the opposite of this.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإيلاء / 15225