Everyday is getting harder :(

Why you have friends who send you nudes when you have girlfriend? You should not have these friends, since it may seem like fun, but it will ruin your connection with your girlfriend and not to meantion it's cheating(not the worst kind but little bit still), so I would advice you to stop this kind of behavior and build deep relationship with your girlfriend, not everything is about sexuality in relationships and that's what makes them special(the combination).

 

Option 1: Dump your gf

Option 2: Ghost that “friend”

Don’t be a b*tch.

 

This is just my opinion, but take it from someone who has been in an open relationship: I wouldn't call an open relationship a real relationship. Supposedly some people can make it work, but for many many people, it usually doesn't last long. A lot of people get into those because they just don't want to end the relationship, or because they want to keep someone available in case they can't find anyone else (or in a more sad case, one or the other has been cheated on and they don't want to go through that pain again at any cost so they create a relationship where cheating is impossible). You're basically glorified fuck-buddies. If you don't believe me, try living with that person while in that relationship. It's all kinds of frustrating, and thus the relationship hits a dead end.
But that's all kind of beside the point. If you have no problem with the relationship and you're just struggling to keep yourself from edging or masturbation, then I'd say just try not being on your phone as much. I'm pretty sure we're all going through those erections that are hard to ignore, but when they do, distance yourself from tech and make yourself busy with something else, and just "ghost" your dick. That's what's been helping me.
Keep at it dude, it's tough but it's doable.

 

From my angle, “Open Relationship” is not a real relationship. Think about it, which one are you being real and which one are you being fake to? Also why would you want to be anyone’s doormat to be used when you are available? So think about the time that one or both is not available for you. That would be a well taught lesson.