She’s not yours it’s just your turn.

Well no shit it’s everyone’s turn.

Very few people get their first choice of partner in life if at all.

Also if you end up letting yourself go and poorly manage the inevitable suffering in your life yeah the risk of you losing said turn is going to rise. It’s not hypergamy or female nature it is human nature. And death do us part is only applicable when the person you are with is still at their core the person you chose to be with and that’s never the case. That’s why job losses or other moments of crisis cause breakups. It’s not about the loss of resources but your reaction and how you cope to them that’s important.

Also we have a saying in psychology.

If your not improving your declining or content. And if your content then that’s even worse then declining because at least while declining you have the ability to see and want something better for yourself. While being content means you have accepted the status quo. Certainly content can lead to happiness and a fulfilling life. However more times than not it is the other way around.

So if you want your turn to last, keep working on yourself loving your life and managing or learning to manage moments of crisis better and chances are you’ll never need another turn again.