I mean just as one consideration:
When you're old, and you're on wife or "partner" no 4, who is in her 20s, who is going to take care of you?
You no longer have value to the woman in her 20s. She's gone, or is not doing her best. For just one thing, she's the sort of young woman who would marry/partner a very old man for his money.
You have alienated all your children bc you ditched their mothers for the New Model. They're gonna take care of you?
This model sustained itself before--thank God--western civilization, and Christianity. It's reviled now and for good reason.
But hey, I'm sure there are great drinking parties at Valhalla or whatever