Double is relatively speaking in this context. And I would base it not on the risk but on the amount of damage. You have a "basic damage" that one of the partners is left alone and has to manage with their income (and possibly less income, because more time is required for the children). You have this regardless of the property. For the property, the potential damage that one of the partners should be able to hold the property alone is added. Therefore, a declining insurance sum can make sense here (and a division).
If there are no children yet, you can, of course, make the whole thing more flexible. However, if children are planned or at the latest when they are there, one should, in my view, rethink the issue.