If my husband asked me to have sex with him in the middle of a serious argument between us when I’m extremely nervous, what should I do?

Islam prescribed that spouses must engage in intimate relations with love and tenderness since Allâh made this a sign for one's piety. He says,
"Your wives are as a tilth for you so approach your tilth when or how you will; but do some good act for your souls beforehand; and fear Allâh, and know that you are to meet Him (in the Hereafter), and give (these) good tidings to those who believe."
(Qur'an 2:223)
The Prophet (peace and blessings be upon him and his family) explained the words of Allâh "do some good act for your souls beforehand" and said, "There are three acts of mistreatment." He [the Prophet] mentioned one of them and said, "A man should not have intercourse with his wife without sending a messenger i.e. foreplay and kisses. None of you should fall upon his wife like an animal" [Reported by al-Dailami in Musnad al-Firdaws through Anas ibn Malik (may Allah be pleased with him).
Though it is a weak hadith, it is put into practice because it is related to good deeds.
The Shari'ah commands a wife who dislikes her husband and conjugal relations with him to be patient to protect the family and preserve rights. Allâh Almighty says,
"It may be that you dislike a thing and Allâh brings about through it a great deal of good."
(Qur'an 4: 19)
If a woman insists on her stance, she may ask for a divorce to prevent disputes which may lead to harm; this is considered undertaking the lesser harm and preventing a greater evil.
It is worthy to mention that because conjugal relations are extremely private and variant, not every sexual act without the wife's will is considered marital rape or violence against her. This is because sexual relations involve matters that are not divulged and which vary from one couple to another. They do not involve open matters which can be judged through evidence.
Ruling
The spouses must resolve this problem through love, mutual understanding and frankness. Each of the spouses must respect the desire of one another, because the marital relationship is based on love and mercy.