He had intercourse with his wife after the first stage of exiting ihram and before doing tawaaf al-ifaadah

Praise
be to Allah. 

If a person has intercourse with his wife
after the first stage of exiting ihram and before doing Tawaaf al-ifaadah,
then his Hajj is not rendered invalid by that, but he has committed sin by
doing it. He has to repent and seek forgiveness from that, and he should go
out of the boundary of the Haram zone in order to enter ihram anew, and do
tawaaf al-ifaadah. 

He also has to slaughter a sheep, and
distribute the meat to the poor of the Haram, and not eat any of it
himself. 

If his wife was in ihram and had
intercourse with him willingly, then she must do the same as him, but if he
compelled her to do that, then she does not have to do anything. 

It says in al-Mawsoo‘ah al-Fiqhiyyah
(2/192): 

(The scholars) are unanimously agreed that
intercourse after the first stage of exiting ihram does not invalidate Hajj…
but there was a difference of opinion as to the necessary penalty.  The
Hanafis, Shaafa‘is and Hanbalis are of the view that he must offer a sheep.
They based their view on the fact that the offence is of a lesser degree,
because of having passed the first stage of exiting ihram, in the case of
men. 

Maalik said – and it was also a view held
by some of the Shaafa‘is and Hanbalis – : He has to offer a camel. Al-Baaji
explained it as being because of the seriousness of the sin when one has
still (not fully) exited ihram. 

Maalik and the Hanbalis regarded it as
obligatory for the one who commits this offence after the first stage of
exiting ihram and before doing tawaaf al-ifaadah to go out of the Haram
zone, and do (another) ‘umrah, because of the words of Ibn ‘Abbaas to that
effect … but the Hanafis and Shaafa‘is did not regard that as obligatory.
End quote. 

Shaykh Muhammad ibn Ibraaheem (may Allah
have mercy on him) said: 

Intercourse after exiting ihram does not
invalidate Hajj, whether it was ifraad (Hajj on its own) or qiraan (‘umrah
and Hajj together, without exiting ihram in between). Rather it only
invalidates ihram, in the sense that it is not valid for him to do tawaaf
al-ifaadah until he goes out of the Haram zone and enters ihram, then comes
to Makkah and does tawaaf al-ifaadah in a valid state of ihram. 

He also has to sacrifice a sheep, to be
slaughtered in the Haram and the meat given to the poor; he should not eat
any of it. His wife must also offer a fidyah of another sheep, if she did
that willingly, but if she was forced, then she does not have to do
anything. End quote. 

Fataawa wa Rasaa’il Muhammad ibn
Ibraaheem (5/203-204) 

Shaykh Ibn ‘Uthaymeen (may Allah have
mercy on him) said: 

A man had intercourse before tawaaf al-ifaadah,
after stoning the Jamrah and shaving his head; what should he do? 

He replied: 

He does not have to do anything except
offer a sacrifice to be given in charity to the poor. And he has to enter
ihram again from outside the Haram zone, so that can do tawaaf in ihram. End
quote. 

Liqa’ al-Baab al-Maftooh
(90/17) 

If he did not go out of the Haram zone in
order to renew his ihram, we hope that his tawaaf is still valid. Shaykh Ibn
Baaz (may Allah have mercy on him) was asked:

A man did not do tawaaf al-ifaadah and he
went back to his country and had intercourse with his wife. What does he
have to do? 

He replied: 

He has to repent to Allah, may He be
glorified and exalted, and he has to offer a sacrifice, to be slaughtered in
Makkah and given to the poor. He also has to go back and do tawaaf al-ifaadah,
because his having intercourse with his wife before doing tawaaf al-ifaadah
is not permissible and a sacrifice must be offered for that. The correct
view is that a sheep is sufficient, or one seventh of a camel or one seventh
of a cow. End quote. 

Majmoo‘ Fataawa Ibn Baaz
(17/180) 

And Allah knows best.