What does 'you're mine, but ill share you' mean from a fwb?

[Anonymous]

I told my friends with benefits (who is the biggest player ever, he had 6 girls and me on the go when I first met him), that I was thinking about going serious with another guy. He said you're mine, ill share you but you're mine'
Tf does this mean

[AnonKuma]

Some guys have like a possessive nature to them so they think or like to think that they have control over something such as him having control over you. He's saying that you're his, but he doesn't mind you have sex with someone else, but at the end of the day he thinks you will always go back to him

[Anonymous]

He thinks you are his sex toy more or less and thinks that regardless if your in a relationship or not < that you are his to use even if you have a boyfriend , best thing to do is get away from him.