My Male cousin invited me over for a threesome with his girl and it kind of left us on bad terms now

So I might even be a douche for this but it doesn't even matter now. This all happened 2 days ago and thought I should share this situation I'm in. I'm 22, and they are both 18.

I sort of grew up with my cousin and we shared many things between us no matter how disturbing it was, then he brought up the idea that he wants to partake in a 3some with his girl and he asked if I can be the 3rd person.

Now don't get me wrong, when he first told me this I completely rejected it since my first thought was that I was going to be in a room with my cousin butt as naked, and that didn't seem like a good idea even in the slightest. But after he justified why I agreed, and it was stuff like he wants to see her take it two places at once, and she's curious about a threesome and that they came to a conclusion for a threesome if he, my cousin gets to pick the male they invite into it.

That happened around a week ago, I agreed since low-key it's been awhile since I've last fucked a girl, and so I started looking forward to it without making it obvious.

So the day comes and I swing on by his house to pick them both up, and upon turning on his street it hit me that I've never seen his girl before, and once I laid eyes on her as they were walking to my car I knew this was going to be fun, I mean hey she had a nice body and so I knew I was going to enjoy myself.

Now everything up until this point is great with my cousin, I asked her what made them want a threesome but I won't share those boring details.

So we pulled up to my house that I inherited from my grandparents, we got inside and went to my bedroom.

We undress, and they both stared at me, because compared to my cousin I am much bigger and thicker, seeing my cousins dick made me feel better about myself and it gave me the courage to really get things going.

Some rules he set were: If he says to stop we all stop, If he wants to switch positions with me we do so, and the last rule was that I had to wear a condom.

I abided, and after a few minutes of getting blowed he got the first turn of fucking her while she sucked on me, and to my surprise 2 minutes later, he stops, he had already reached his climax and nutted deep in her.

Now this is where I will be honest, this gave me a dominant complexity in my head, I was bigger, I had more experience with women so I know what they like and don't usually like, and lastly was that I knew I could last longer than 2 minutes.

So once he pulled out I grabbed her and pulled her ass towards me, I laid my meat on her ass playfully talking to her, and once she gave me the green light that she was ready, I slid it in and started giving her the best sex she's likely ever had, her moans were louder, she started begging, and whimpering

My cousin just sitting at the other end of the bed just watching us fuck, as he was recharging so he could get his turn again afterwards. After some time of being deep in her, I took a glance at him and realized this isn't how he thought this would be.

He likely realized this isn't as enjoyable as he thought it was going to be, so he told us to stop, but this is were everything went wrong, the moment he yelled to stop, she screamed claiming she was about to cum and told me to keep going no matter what.

So in my head it was either stop, or keep fucking her till she came

I decided to keep going, and after 20 more seconds we both came at the same time, hearing her screams at the moment of climax made me cum too.

I pulled out and he walked out of the room, so it was just the two of us in there. She then proceeded to tell me he's never made her cum before and watching her cum to another man most likely broke him.

He ended up leaving the house in an Uber, meaning I have to take her home in my car alone now. 30 minutes later I dropped her off at her house, and on my way back home I started to think how fucked of a day I had.

Yeah I had great sex with a beautiful woman, but I likely destroyed the relationship with my cousin for simple not obeying to his order of pausing the fuck session.

Now I don't know what to do, she gave me her number and I'm assuming she might want to go for a round two again but I need to think on this. This all happened 2 days ago and I'm thinking of making the phone call to ask whats going on.