What is the ruling on one who had intercourse during the day in Ramadan without ejaculation, thinking that only ejaculation invalidates the fast, and he does not know the number of days he did that?

Intercourse during the day in Ramadan invalidates the fast and necessitates expiation, even if ejaculation does not occur. It is the most serious of the things that break the fast. Ignorance of this is not an excuse if one is among the majority of people who are not ignorant of this ruling, as it is considered a shortcoming in seeking knowledge. Expiation is obligatory for every day in which intercourse took place. This expiation is freeing a slave; if one cannot find one, then fasting for two consecutive months; if one is unable to do that, then feeding sixty poor people. The wife is obligated to make up the fast, and it is more cautious for her to perform the expiation. If you do not know the number of days you invalidated by intercourse, then you must make up the number of days that you believe most likely fulfill your obligation. The more cautious approach is to make up the fast until you are certain that your obligation has been fulfilled.