@Mate1212 I get it. But the best you can do is be better yourself. I have a girlfriend myself and I'm not afraid of losing her, because I know I'm the best fucking option she can possibly choose from.

She finds a guy better than you, she cheats. It doesn't get any simpler than that.

Now I also get it that the insecurity is always going in at the back of the mind but if you work onto being a better yourself every day your mindset will shift entirely. You'll no longer feel insecure or a loser because the subconscious will start believing that you're actually building something. Work out daily, work towards developing your skills, do what you like and actually start living life in the real world instead of your head. This will tremendously help.

Posting that you're insecure about being cheat on will only end up in her cheating because you are a 'loser'. Because losers ain't got options and will cry if their girl leaves. Don't be a loser. And don't be afraid of her cheating. Who knows if fuck-your-bitch richie will have eyes on your girl and wants to fuck her (spoiler: she'll go with fuck-your-bitch richie). Only two solutions, there are: 1) Stop caring about being cheated on. 2) Be a better choice (IN THE EYES OF YOUR GIRL) than fuck-your-bitch richie.