Just guessing, which is that it was a political marriage to consolidate an alliance between countries or factions.
Spot on.
Seems to me kind of a non-starter to cement an alliance with a marriage of people who can’t or don’t have a relationship. Were there no women in France? (where Isabella was from)
Not disputing the propaganda, but they would hardly have said otherwise. Within the next couple years, they tried to force her into other political marriages, which she refused out of loyalty to the deceased Richard and she was sent back to France.