Divorced and vacationing

Apparently it's a trend for divorced families to vacation together -- "ex"-spouses, "new" spouses, step-children. Yahoo! News reported on the topic. I found myself scratching my head throughout the piece. If these couples are able to spend an amicable week together on vacation, then what was stopping them from working on their marriage? But then the most heart-dropping line was dropped:

"When I want to be short or get irritated or whatever I can't because Ace is standing right there," she [Meredith Morton] said. "It's not like it's a huge sacrifice," she added. "Honestly, the gift that I give Ace by having us both in the same place" is worth it.

Ms. Morton, if it's worth giving your son the gift of being with your "ex"-husband for a week or two, then how inestimable of a gift to give the witness of your marriage for a lifetime?