You are a Male, you're not programmed to be obsessed over a single woman. A man needs to plant his seed in many gardens, your artificial commitment to your Oshi is causing you to become psychopathic. Your brain just wasn't built for it.

If you have many Oshis, or preferably, real female prospects, it won't hurt very much when you see them interacting with males.

Do yourself a service and stop saving yourself for one person. That's female behavior.