Do I Have to Do Ghusl If I Don't Ejaculate?
Question

If intercourse takes place and there is no ejaculation, is Ghusl required? Or is it only required if ejaculation takes place?
Praise be to Allah.“The scholars unanimously agreed that Ghusl is required in the event of intercourse .” (Al-Mawsu`ah Al-Fiqhiyyah, 3/198) 
If a man has intercourse with his wife, they must both do Ghusl even if there is no ejaculation . 
Abu Hurayrah (may Allah be pleased with him) narrated that the Prophet of Allah (peace and blessings of Allah be upon him) said: “When a man sits between the four parts (arms and legs of his wife) and has intercourse with her, then Ghusl is obligatory .” (Narrated by Al-Bukhaari, 291 and Muslim, 525 who added: “Even if he does not ejaculate .”
 Al-Nawawi (may Allah have mercy on him) said in Sharh Muslim: 
“What this Hadith means is that the obligation of Ghusl does not depend on the emission of semen, rather when the tip of the penis disappears into the vagina, then Ghusl becomes obligatory for both the man and the woman. There is no dispute concerning this matter today, although there was a difference of opinion among the Companions and those who came after them. Then there arose consensus on what we have mentioned.”
Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) said: 
“It is clear that Ghusl is required in this case , even if he does not ejaculate. This is something that is not known to many people, so you may find that this has happened to a couple, but they do not do Ghusl, especially if they are young and have not learned much. This is based on their idea that Ghusl is only required when ejaculation takes place, but this is wrong.” (Ash-Sharh Al-Mumti’, 1/223) 
It says in Fatawa Al-Lajnah Ad-Da’imah (5/314): 
“Among the things that make Ghusl obligatory for a Muslim are: the emission of semen whilst sleeping; the disappearing of the tip of the penis into the vagina even if no ejaculation takes place; the emission of semen with pleasure when one is awake, even if no intercourse takes place; and menses and postpartum bleeding in the case of a woman, in which case she must do Ghusl when the bleeding stops .”
And Allah knows best.