If you're busy would you let your partner have a playmate to fill their time?

Imagine you're too busy to satisfy the normal role you play in your relationships would you mind if your partner gained another to satisfy their needs?
This is something my ex suggested to me. I ended it because he was actively pressuring me to do so, despite me not needing/wanting it.
If you're busy would you let your partner have a playmate to fill their time?
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