Because he wants to make it clear to you that he will not be monogamous. He’s not a one-woman man, like Raven said. If you choose to sleep with him you’re agreeing to the situation.
You can’t force him to choose you and you only. He has the right to do what he wants, he’s been honest with you. The only thing you can control is yourself, and you can choose to walk away. If you want a monogamous relationship, he’s not your guy.
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