Healthy Relationships Support Group
No relationship is perfect. A long-term relationship requires constant effort to understand each other, fix misunderstandings, solve problems and continue to grow as both individuals change and evolve. How we deal with our misunderstandings is the focus of this community. Join us to find support, get advice, and share your experience with your relationship.

There is also something to be said about making an effort to not indulge that kind of thinking. If you know it's not reasonable then when that feeling comes over you, why sit in that feeling? Instead, try redirecting your thoughts or remind yourself that jealousy is a ridiculous emotion.
You may want to talk to a therapist if you find you really are struggling.
I wonder for you if it's more a depression thing. That's kind of what it sounds like. Maybe I'm wrong, but whatever the issue, I think therapy can be super helpful. And you really have to do it for yourself, because you don't deserve to feel this way either. You want to be a happy and whole person independent of your relationship.
When you feel the jealousy monster coming just choose to stop thinking about it, go do something different and keep busy. You need to relearn the habitual way of thinking about it.
I struggle with it too, it makes me feel sick and just ill. Such severe anxiety usually stems from a fear of being out of control of things ( her) but you can learn to overcome that. So it is really a control issue or the fear of what happens being out of your control, as it is down to her, your gf, what happens. You can control how you feel though. Only you can do that. So try what I suggested and try to control those emotions. It takes practice but you can do it. You are worth it. x
If you are jealous of her make friends, she should be introducing them to you before going out to do things with them.
I personally do not hangnout with male friends because I don't think it is appropriate for me to do that when I have a man.
I will invite male friends to meet my BF and avoid being with them 1:1,
But that's just me.
But, I do think it depends on the extent of the person's jealously, like if it becomes controlling, ie your partner gets enraged if you speak to another man at the grocery store, is constantly accusing you of flirting merely because you're shooting the breeze with your mail man, or if he tells you what to wear so others won't be attracted to you, if he makes your life effing hard every single time you're leaving the house, accuses you of having affairs with coworkers based on nothing but an over active imagination, that crap is unreasonable and shouldn't be indulged.
I'm also not sure what would make you feel jealous, if she is not doing anything to make you jealous. There seems to be a fair bit of contradiction in your last post, and I'm wondering if there is more to this. Often, when one is not trusting, jealous and accusatory, there is either something going on with their partner, or there's something going on with them, and they're reflecting it onto their partner. There's always a reason why things happen, and perhaps you're not looking at the full picture.
A way to untangle the feelings and thoughts that you're struggling with, is to turn around, and follow your footsteps back to where they originated, and connect the dots. There's always a reason for our madness, and facing the hard truths of where those footsteps originated can set you free from torment, and stops the mad cycle of endless replay.
I would consider therapy to help you work through this... It may be a wonderful gift to you in order to rid yourself of these awful feelings if they have nothing to do with your relationship now other then within you.. Big hug....xo