no, it should not get destroyed. send a copy of the parent insert and child insert pages so i can examine the code.
this is very similar to showing orders and order details on a page. a good way to do this is by creating two separate results pages in Data Assist, one for the parent table and a second for the child table, then use plugins to display them both.
see the "Displaying Relational Tables with Plug-ins" tutorial on the Data Bridge support page for details: