Praise be to Allaah. The parents have great rights, but the husband has a greater right. It is not permissible for either party to abuse the rights of the other.
If the wife thinks that her husband has wronged her parents, she should advise him and remind him that the aayah (interpretation of the meaning), “… and live with them [wives] honourably…” [al-Nisa’ 4:19] includes treating her family well too, because that makes her happy, and it includes not harming them, because that upsets her.
By the same token, if one or both of her parents abuse her husband’s rights, she should advise them and remind them of the seriousness of backbiting, wrongdoing and aggression. If they order her to do something and her husband orders her to do the opposite, then her husband takes precedence, because his rights are greater in sharee’ah. This does not mean that she should forget about their rights; this is the guideline she should follow in cases where there is a conflict.
With regard to your second question, it is not haraam according to sharee’ah for a man to have intercourse with his wife after the nikaah (conclusion of the marriage contract) and before the wedding party. Whatever happened after the nikaah is halaal (permissible), so there is no scandal involved and no need to fear the consequences. If a man divorces his wife after the marriage has been consummated, then she is entitled to keep the entire mahr (dowry) If it is possible for mediators to try to bring you back together in accordance with sharee’ah and following the proper etiquette, then this is better. And Allaah is the source of strength.
Ref: Islamqa
Tags: Husband mistreating father in law, Husband is not behaving properly with family of wife, intercourse before wedding party, intercourse before waleemah, intercouse before reception, Husband harassing wife's family, Husband abusing family of wife