Had a threesome with my friend and his girlfriend while my girlfriend was home

Hi Reddit, idk who to tell I’m still in disbelief this even happened. I (24M) went out drinking with my two friends who are a couple (25f 25m) and with my girlfriend (25f). All night we’re getting along hitting different places to drink, eventually we all get back to my place and start settling down, my girlfriend goes to bed and my friend and his girlfriend go to the guest room. I go to the kitchen which is right next to the guest room, at this point my girlfriend has fallen asleep. When I go to the kitchen I see them having sex right there with the door open, I linger for a second watching because i can see her riding him and everything is right out in the open. Now at this point we are all very drunk, My friend instantly noticed me and motions for me to come closer. He whispers in her ear something about how I’m watching them and she instantly starts saying my name moaning while my friend is in her. She’s saying how she wants me and keeps begging to suck me off, begging to pull my pants down. I wrestled with horny thoughts for a second and said no but she looked so hot riding my friend, I eventually pulled my pants down and stuck my boner right in front of her face. She instantly grabbed it and stuck it in her mouth. I let her suck me for a couple minutes while she was riding my friend still. Then I leave the room and am like damn I really just did that. I go back to the living room and can still hear them fucking so I go back and she sees me and starts begging me to just fuck her. My friend motions me over again and he pushes her off him to let me in. Horny thoughts took over and I grabbed her by the hips and start fucking her missionary while my friend watches. Then she asked to ride me so we switch to that. She then keeps moaning and asking me to cum in her, all the while I’m trying to cover her mouth and make her quiet because my girlfriend is sleeping in the other room. I eventually fill her up, look over at my friend and mouth ”is she on birth control?” He nods, I get up and instantly leave the room go to the bathroom and wash off my dick. Now I feel bad and am just hoping no one says anything about the whole situation.