I am probably overthinking all of this. This is probably why it's happening to me, but i don't know how to not overthink it.
Yes, I think you are overthinking it. And, it is likely to be your "belief system" that is causing you to overthink it. You didn't state why you don't want to ejaculate through masturbation now that you have a girlfriend. So, I really can't help you with that.
However, I can tell you this. The bible does not mention masturbation. The previous poster suggested that you study Onan (Genesis 38). Onan was killed by God because he refused to "become seed" for his brother. His brother, Er, had been previously found evil by God and killed. It was the law under the Levitical priesthood that a deceased man's brother should sire children with the brother's widow to give his brother heirs. The narrative states that Onan "spilled his seed on the ground" instead of ejaculating inside Tamar so as to prevent her pregnancy, because he "knew that the seed should not be his". Just a simple reading of the passage and what it says indicates that this is why God was angry with Onan, and why God killed him.
The story of Onan is used, in a manner that I believe erroneous, to create doctrines regarding masturbation, when masturbation is not at all the act being described in the story. It is used to create doctrine of "desecration of seed" which doesn't seem very relevant to the story, either.
How do you guys go so long with no sexual release at all? Or even touching yourself?
Personally, I don't. I don't even try. I'm married, and 59 years old, and masturbate to ejaculation nearly every day when my wife and I don't have sex. Our sex is somewhat less frequent than it used to be, maybe on the order of once per week now. If I don't masturbate, a couple days goes by, and I start to have a "wicked, wandering eye" which looks at ladies. Being faithful to my wife is a #1 priority to me, in my life. I don't like having to endure
temptation, and masturbation, is for me, a mode of avoidance.
I don't believe that masturbation is sin. The reason for this, is that virtually every conceivable sexual perversion is discussed in the bible, and condemned by it. But not masturbation. I can either think that nobody masturbated in those days (rediculous) or I can think that God just doesn't care about it.
Personally, I believe that God would have said so if He did not want us to do it. He has no problem telling us other things which He doesn't want, the bible is not at all "prudish" about how it describes sexual behaviour. It is explicit and straightforward.
i'm scared that this all won't go away.
I am, too.
My brother, Jesus said "my yoke is easy, and my burden is light". This does not sound either "easy" nor "light", to me. And I've somewhat learned (not that I've attained to it) that when something is not both "easy" and "light", I'm shouldering somebody else's yoke.