oomis: Sure it is assur to go to the secular courts even if it “involves secular laws”. Besides, halacha tells us who should have custody, halacha tells us how to split the assets, and it is prohibited according to halacha to use non-Jewish laws on these matters instead of basing the decision on how Jewish law/halacha rules on these matters. “
When there are issues of abusive relationships, the secular courts WILL be involved, whether the yidden involved want them to or not. Dina d’malchusah dina. But I understand what you and others have said.