Girlfriend problems

I'm starting to have doubts about my relationship with my girlfriend.

My girlfriend is fucking amazing, both in looks and personality. She's probably one of the most attractive girls that I've ever seen. Blonde, 9.5/10 face, D cup breasts, she's just all around gorgeous. I'm shocked that out of so many guys out there, she's with a loser like me.

Anyway, we've been together for about two years. We're both 19 and we met each other during our college's orientation, and we've been together ever since. Just two weeks ago, we decided to take our relationship "all the way".

It was the first time I was ever having sex. My knees were shaking so hard that I almost fell down. I was kind of worried about my penis being too thin (it's 7 inches in length, but the girth is only 4.75"), but my girlfriend just kept telling me that I was being too self-conscious. We had sex, and it was great even though I could barely feel my dick because of the condom. (She insisted I wear a condom just in case, even though it was my first time having sex). She moaned during the sex, but it sounded kind of fake, but she said she enjoyed it.

So throughout the last couple of weeks we've had sex like 10 more times. After we had sex again about a week ago, she said I was good, but that I should try jelqing to increase length and thickness. I didn't like that she said that, and I thought 7 inches is pretty big compared to the average, but I guess maybe I'm just being nitpicky.

So just yesterday, me, my girlfriend, and her friend were in her dorm talking, and she suggested that we have a threesome (not a permanent relationship, but just a one-time thing). Her friend is a really cool person so of course I agreed. The three of us got naked and I started thrusting into my girlfriend first because, well, she's my girlfriend. I came too early though, and that kind of sucked.

So as I was throwing away the condom, then her friend got on top of my girlfriend. His cock was the biggest I've ever seen. It must have have been 9 or 10 inches long, and its thickness was like that of a coke can. He started thrusting into my girlfriend and she started wailing like I've never heard. She was screaming his name, "Oh Tyrone oh Tyrone" and moaning with passion. She turned to him and said "I want my vaginal walls to be in direct contact with your aesthetic black cock. No layer of rubber shall be between us!"

He took off his condom and started thrusting again. She started moaning so loud that I was afraid the people in the dorm next to ours would complain. My girlfriend was a religious Christian all her life - that's why we didn't have have sex for two years of being together - but when Tyrone was pumping into her, she said "Jesus can go to Hell! The BBC is my God!" Then she said "Tyrone, I want you to cum inside me. I want your black seed in my body." And he came inside her.

I was talking to her this morning and she said that she is still going to be my girlfriend because she likes my personality, but for sex she wants to have sex with Tyrone instead of with me (just the two of them). I asked her if we could maybe have threesomes sometimes instead, and she said I was a control freak and that this is the 21st century and she doesn't have to listen to me just because I'm a man.

So what does the misc think? Am I being too restrictive? I guess it's her business who she has sex with, but it kind of makes me feel uncomfortable to be in a relationship with a girl where she's having sex with another man instead of with me. Should we stay together?

also inb4 pee in her butt