When I found this out I actually thought that this was perhaps the reason why he'd been married off to the lady mentioned.
It certainly might've made for an interesting pro-French party in Madrid during Carlos II's minority.
In fact, both matches were planned for circumstantial reasons, and then I saw that son of Marie Mancini did marry a Medinacelli, and Juan Jose was a candidate for hand of either Marie or Hortense. So "because reasons" actually worked.