It should be clear that breaking a single day of fast through sexual intercourse entails very serious penalty. No one who is fasting should do foreplay with his or her spouse in the daytime of fasting if there is a genuine risk of overstepping the boundaries. If there is no such fear, then light touching or kissing, when not accompanied by sexual desire, is permissible. When a young man asked the Prophet (peace be upon him) whether he can kiss his wife while fasting, the Prophet replied “no,” but when an older man came and asked him the same question, he replied “yes.”

Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following: If you deliberately engaged in foreplay while fasting and ejaculated, then you have violated the sanctity of Ramadan. You must make up for the violation by fasting the same day. It is also recommended that you offer something by way of charity as well in order to expiate for your mistake.

If, however, you ejaculated following intercourse being carried away by foreplay, then you ought to fast two months consecutively. If you find this rather difficult, then you must feed sixty poor people for that single day of fast you have missed.
Ramadan is a blessed month of infinite blessings, and it is our Islamic duty to observe its sanctities. So, while fasting, we must guard our fasts against acts or words that nullify it. So, in the future you should be extremely cautious, for the Prophet (peace and blessings be upon him) said, “Whoever breaks a single day of Ramadan fast without a valid reason cannot hope to make up for the same by fasting an entire month ” (Abu Dawud and At-Tirmidhi).

It is also worth remembering in this context that while we are ordered to restrain ourselves from sexual relations with our spouses during the days of fasting, we are certainly allowed to have sexual relations without any inhibition during the night. Therefore, we must abstain from the things that Allah has forbidden while enjoying His allowances and permissions.
So, as a practicing Muslim you must never take this matter lightly. It is important for you in the future never to indulge in such activities while fasting. May Allah make us among those who reverence the sanctities. Ameen.