<human>: Can you condense the text into three sentences or less?

[Here] is the backstory for this situation written on the wrong throwaway.

This girl who I vented to (in front of her boyfriend) has lost her mind and has started harassing my girlfriend. I can't do anything to stop it because I don't have her contact information. However, she told my girlfriend to tell me to "stop trying to hook up with her because she's engaged." My girlfriend refers to this girl as my mistress and said she will no longer believe anything I say and has no trust in me.

She then mentioned that she doesn't want to touch me because of my "NEED to masturbate daily." She said she can no longer lie to herself and think I DIDN'T have a physical (or emotional) relationship with this girl. She doesn't believe that I haven't. Reddit, I haven't. She said she won't talk to me until I get STD tested and still won't believe I didn't have a relationship with this girl. She said she'll be waiting until I make the appointment.

I haven't responded to her 14 page text yet because I'm in shock. My girlfriend is my only sexual partner ever and the only girl I've kissed in the past 4 years. I AM NOT getting STD tested. I will not give in to that because nothing I ever do makes my manipulative girlfriend trust me. And I will not falsely admit I did something with this stupid girl.
<bot>: What do I do now? I did not have any relationship with this girl who is harassing my girlfriend and my girlfriend refuses to talk to me until I get STD tested. Will she EVER even trust me again?