You may engage in foreplay with your wife while fasting, kiss her, embrace her and touch her, if you are certain that you will not ejaculate or have intercourse. If you engage in foreplay with your wife until you ejaculate, you have committed a grave sin. By doing so, you invalidated your fast and you have to offer expiation.

Intercourse at night in Ramadan is permissible. Night lasts from when the sun first sets until (true) dawn comes. It is haram to have intercourse with your wife during the day in Ramadan and it is one of the things that invalidates the fast.

If the muadhdhin gives the adhan at the time when Fajr comes, then he must stop having intercourse as soon as he hears the adhan. If he does not do that, then he must make up the fast as well as offering the expiation.

1- If a man had intercourse with his wife while fasting and he was unaware of the ruling, and he thought that the kind of intercourse that is haram is the kind in which ejaculation occurs, then he does not have to do anything. 2- If he knew that intercourse is haram, but he did not know that there is expiation for that, then he has to offer the expiation.