A woman who agreed to sex might still be the victim of rape, the High Court has ruled.
The most senior judge in England and Wales and two other judges said there was consensual penetration, but the man behaved aggressively and ignored the woman's demand that he not ejaculate.
The woman had challenged a decision not to prosecute the man for rape and sexual assault.
The judges have ordered prosecutors to review their decision.
Prosecutors had decided not to charge him as it would be "impossible to prove" that the man's decision was not "spontaneous" and "made at the point of ejaculation".
'Control over her'
Handing down a written ruling, the three judges said the man had been controlling and aggressive during sex.
On the specific incident in question the woman consented on the clear understanding that the man would not ejaculate within her vagina.
The ruling said: "She believed that he intended and agreed to withdraw before ejaculation. (He) knew and understood that this was the only basis on which she was prepared to have sexual intercourse with him.
"In short, there is evidence that he deliberately ignored the basis of her consent to penetration as a manifestation of his control over her."
Shortly after penetration - and without giving the woman "any chance to object" - the man had said he would be "coming inside her" and had added "I'll do it if I want".
Definition of rape
Judges were told that the man had "ejaculated before she could say or do anything about it", and she had become pregnant.
Lord Judge, Lord Chief Justice of England and Wales, Mr Justice Fulford and Mr Justice Sweeney at a High Court hearing in London, added: "She was deprived of choice relating to the crucial feature on which her original consent to sexual intercourse was based.
"Accordingly her consent was negated.
"Contrary to her wishes, and knowing that she would not have consented, and did not consent to penetration or the continuation of penetration if she had any inkling of his intention, he deliberately ejaculated within her vagina.
"In law, this combination of circumstances falls within the statutory definition of rape."