What is Allowed (Physically) to be Seen Between Husband and Wife
It is not Haraam (impermissible) for a man to look at anything from the body of his wife and neither is it the case in regards to the touching of it.
However; it has been said: that it is disliked to look at the private parts, and it has been said: that it is not disliked except at the time of sexual relations. And Allaah knows best.
Shaykh ul-Islaam Ibn Taymiyyah
Jaami’ al-Masaa’il le Shaikhil Islaam Ibn Taymiyyah Majmoo’ah ar-raabi’ah (book four in the series) page: 358