Praise be to Allah.
Saying “fate decreed” is not correct, because the One Who wills and decrees is Allaah, the One, the Subduer, may He be glorified and exalted. We have already discussed this in the answer to question no. 8621.
Breaking the fast in Ramadaan for no reason is a major sin, and the one who does it is a faasiq (rebellious evildoer) who has to repent to Allaah from this major sin.
It was narrated that the Prophet (peace and blessings of Allaah be upon him) issued a stern warning to the one who breaks the fast in Ramadaan for no reason.
Al-Haakim narrated that the Prophet (peace and blessings of Allaah be upon him) saw the punishment of the one who breaks the fast in Ramadaan for no reason, He said: “We saw some people hung up by their Achilles tendons, with the corners of their mouths torn and pouring with blood. I said, ‘Who are these?’ He said: ‘These are the people who broke their fast before it was permissible for them to do so.’”
Classed as saheeh by al-Albaani in al-Silsilah al-Saheehah, 3951.
Based on this, this husband has to fear Allaah and not take the matter of fasting lightly, for it is a serious matter.
You should not obey him in this matter, for there is no obedience to any created being if it involves disobedience towards the Creator.
Breaking the fast in Ramadaan and making it up later on is only prescribed for those who break the fast for a legitimate reason such as sickness, traveling etc. But if a Muslim breaks the fast in Ramadaan for no reason, he exposes himself to the wrath and punishment of Allaah. We ask Allaah to keep us safe and sound.
See also question no. 38747.
Intercourse is one of the things that break the fast, and it is one of the most serious of such things in terms of sin. Hence kafaarah (expiation) must be offered for it.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said in Fataawa al-Siyaam (p. 337):
The one who has intercourse during the day in Ramadaan when he is fasting and is not traveling has to offer a burdensome expiation, which is freeing a slave; if he cannot do that then he must fast for two consecutive months; and if he cannot do that then he must feed sixty poor persons. The same applies to the woman if she was willing, but if she was forced then she does not have to do anything. If they were traveling then there is no sin on them and they do not have to offer any expiation, and they do not have to refrain from eating for the rest of the day, but they do have to make up that day, because fasting is not obligatory for them (as they are traveling). If a person had intercourse when he was fasting in his own country and was one of those who are obliged to fast, five things result from that:
1-It is a sin
2-The fast is invalidated
3-He has to refrain from eating etc for the rest of the day
4-He has to make up the fast
5-He has to offer expiation.
The evidence for that is the hadeeth of Abu Hurayrah (may Allaah be pleased with him) who said: Whilst we were sitting with the Prophet (peace and blessings of Allaah be upon him), a man came and said, “O Messenger of Allaah, I am doomed!” He said: “What is the matter with you?” He said, “I had intercourse with my wife when I was fasting.” The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Do you have a slave whom you can set free?” He said, “No.” He said: “Can you fast for two consecutive months?” He said, “No.” He said, “Can you afford to feed sixty poor persons?” He said, “No.” The Prophet (peace and blessings of Allaah be upon him) fell silent for a while, and whilst we were like that, a basket of dates was brought to the Prophet (peace and blessings of Allaah be upon him). He said: “Where is the one who was asking?’ He said, “Here I am.” He said: ‘Take this and give it in charity.” The man said: “To someone poorer than me? O Messenger of Allaah, there is no family between the two lava fields (i.e., in Madeenah) poorer than mine.” The Prophet (peace and blessings of Allaah be upon him) smiled until his eyeteeth became visible, then he said: “Feed it to your family.” Narrated by al-Bukhaari, 1936; Muslim, 1111.
If this man cannot fast or feed the poor, then the obligation to offer expiation is waived, because Allaah does not burden any soul beyond its scope, and there is no obligation if one is unable to do it. It makes no difference whether there was any ejaculation or not, so long as intercourse has taken place. This is unlike the case when ejaculation takes place without intercourse, for which no expiation is due, rather this is a sin, and the person must refrain from eating etc for the rest of the day, and make the day up.
He was also asked about a man who forces his wife to have intercourse during the day in Ramadaan, and replied:
It is haraam for her to obey her husband or to allow him to do that in this case, because she is observing an obligatory fast. She has to resist him as much as possible. It is haraam for her husband to have intercourse with her in this case, but if she cannot stop him then there is no sin on her, and she does not have to make up the day or offer any expiation, because she was forced to do it.
Fataawa al-Siyaam, p. 339.