Loved your question! So....let's talk about the vows and promises first.You are absolutely right that vows matter... They are important but do you really think every promise made in life is always fulfilled exactly as intended?Sometimes, even when we love someone deeply and genuinely want to keep our promises, life doesn't always go according to our intentions. There are moments when promises break, not because we wanted to break them, but because circumstances, responsibilities, or situations lead us there. And I'm not talking only about men here. The same applies to women as well. Every human being, intentionally or unintentionally, can fail to keep a promise despite having the best intentions.Now....coming to your second question about multiple marriages being only for heirs that isn't entirely true.Yes, producing an heir was certainly one reason. But... it was never the only reason. As you mentioned, why couldn't one marriage be enough? Well, it wasn't as though a queen would only have one child. However...there was no guarantee that the heir they desired would be born. That was one concern.But beyond that, politics played a massive role. In those times, almost everything revolved around politics, alliances, power, and stability.If a ruler married a princess from another kingdom, that marriage often strengthened political ties between the two states. It could bring military support, trade advantages, diplomatic security, and sometimes even influence over another kingdom in the future. Many royal marriages were decisions based on political gain, loss, and strategic interests rather than personal desires.And you are absolutely right about another thing as well.