Response: Yes, it is permissible for one who is fasting to kiss his wife and play with her during the day in Ramadhaan. However, if he excretes semen then his fast becomes nullified. If this occurs during the day in Ramadhaan, it is obligatory he refrains (from all that which nullifies the fast) for the rest of the day and it is obligatory that he makes up the fast for that day. If this occurs in other than Ramadhaan, then his fast is nullified but it is not obligatory for him to refrain. However, if his fast was that which was obligatory upon him, then it is obligatory he make up that day. If the fast was supererogatory (naafilah), then he doesn’t have to make it up.
Shaykh Ibn ‘Uthaymeen
Fataawa Ramadhaan – Volume 2, Page 454, Fatwa No.383.fatwaonline.com