All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Your Hajj is valid and there is no harm in having intercourse with your wife because it took place after the major termination of Ihraam (after which one is allowed to do the acts which were previously forbidden during Ihraam, including sexual relation) on condition that your wife also has made the major termination of Ihraam. However, it would be a mistake if you pelted Jamrat Al-Wusta on the eleventh day and Jamrat As-Sughra on the twelfth day without pelting the other Jamraat. That is because Hajj obligations include pelting the three Jamraat – Sughra (smallest), Wusta (medium) and Kubra (biggest) – on the eleventh and twelfth days for the pilgrim who departs Mina early (on the twelfth day of Thul Hijjah) and on the thirteenth day for the pilgrim who delays his departure (until the thirteenth day of Thul Hijjah). Every Jamrat is to be pelted with seven pebbles.
By leaving casting Jamraat, a pilgrim is required to offer a sacrifice, which is one sheep or one seventh of a camel or a cow, to be slaughtered and distributed among the poor people in Makkah. However, you may authorize someone in Makkah to offer the sacrifice on your behalf. For further information, see Fatwa 89643.
Allaah Knows best.