A man has 2 wives and wife number 2 goes to visit her umm on her off weekend and is due back on her Monday but didn't make it back. Is it permissible for the man to go stay at wife number 1 house when it's not her not even though wife number 2 is not home for her night?

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 is His Slave and Messenger.

If the husband gave his wife permission to go to her parents’ house and to come back late, this does not forfeit her right to the overnight stay and the husband should make it up for her on another day(s).

The Shaafiʻi scholar Al-Bujayrimi wrote,

“Another example is when she asked (her husband's) permission to go to her father's house and he approved, and she went and stayed overnight on her turn. In this case, she is still entitled to her right to the overnight stay even if she stayed there for days. This is implied from what they (the scholars) have said about traveling, as (going to her father's house) is not (even) considered traveling.”

Allaah Knows best.