All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
It is not permissible for a man to have intercourse with one of his wives in the presence of his other wives, regardless of whether they agree to that or not.
Ibn Qudaamah, may Allah have mercy on him, said, "If his two wives agree that he has sexual intercourse with one of them while the other one is watching, then this is not permissible because this is debased and involves lack of magnanimity, so this does not make it permissible by their consent.” [Al-Mughni, 7/301]
As regards in Paradise, we do not know of anything that is mentioned in the Shariah texts regarding this. It is well known that Paradise and what will happen in it is a matter of the Unseen which cannot be known except by the texts of revelation. There is no doubt that Paradise is the House of Bliss and therein is what the souls desire. However, a wise person should preoccupy himself with what brings him closer to Allah and to His Pleasure and to entering His Paradise.
Allah knows best.