She was experiencing istihadah, and her husband would have intercourse with her.
حدثنا أحمد بن أبي سريج الرازي أخبرنا عبد الله بن الجهم حدثنا عمرو بن أبي قيس عن عاصم عن عكرمة
أنها كانت مستحاضة وكان زوجها يجامعها
No references are available.
[Its chain of transmission is daif] Bayhaqi (1/329) collected it from the hadith of Abu Dawud through him, and Munziri criticized it as flawed. See hadith no. 305. The basic hadith has many corroborating reports.