How do you feel about your spouse/significant other fantasizing about other people while masturbating?

[tia]

People handle it easily because they DON'T think about it. I don't want to know who my partner fantasises about, it's not my business to be in his head. In fact, the question has never been asked. I don't need to know what goes on in his head, and he wouldn't want to hurt my feelings by telling me. It's like asking someone what they're thinking - it's invasive. Not telling you 'I was thinking of ..... When I was ....' is not called 'sheltering' you, it's called keeping your private thoughts private.