<human>: Condense the text into a few key points

For a few months now I've been getting turned on by the idea of my gf having sex with another guy either in a threesome or where i watch her have sex with him. I haven't talked to my gf however for a couple reasons. One is that i don't know how she'd take the news of me telling her about i think about her having sex with another guy. I don't want her to see me different if i told her. I also know she sees things like swinging in a more negative view. Another reason for me is that although i like fantasizing about it, the idea of it and the physical act of doing it are big. I tend to be somewhat jealous when she talks to other guys, but not overly jealous or anything like not allowing her to hang out with guy friends or anything like that. So I think about how there's a chance i could regret it afterwards or while she's in the act of having sex with another guy.

Lately we've also started watching porn while we have foreplay and also during sex. We go through the categories and say which ones we'd be fine watching. She's said yes to ones like threesome and groupsex but no so double penetration and cuckold (she didnt know what cuckold was so i just told her it was when a guy lets his wife/gf have sex with another guy). I've started asking her things like what she likes about the videos (she says things like she likes how the girl is being fucked) and if she wished she was taking part (this only happened in one video with a lesbian threesome). In the times i've done that she seemed into it, especially the threesome one. I haven't asked her though if she'd like being the girl in the video having sex with the guy since i'm afraid she'll react negatively about it.

Basically im not sure how i can bring this up to my gf and have my fantasy done in someway without her seeing me differently for it if she's not into the idea of it.
<bot>: Fantasize about my gf having sex with other men, not sure how to talk to her about it and afraid of how she might react.