A bit?

Relationships are made or broken by the mindset(s) of the people involved - if both parties are accepting of the distance and can come to an agreement over communication and safety, and contingencies ("if you or one of the kids gets hurt I'm coming home for sure") there's no reason a long backpacking trip can't work for them. There's always the risk that the separation will have unintended results, of course. But there are plenty of other circumstances that can damage relationships. The initial hurdle is for the non-backpacking spouse to understand that the desire for a long trip is not a reflection on the relationship. Unless, of course, it is - in which case there are deeper problems afoot that aren't being addressed, that have nothing to do with backpacking.

I go out on short trips with a few retired gentlemen from time to time whose wives are grateful that they are with my group - even a short trip is intimidating for some spouses. Perhaps a test trip longer than a weekend (5-7 days) would help answer questions before the Big One.