Lost my virginity by cheating with my gfs ssbbw friend

So my friends and some of my gfs friends wanted to have a beach party for our last days of summer so i go over to my gfs house to change and give her a ride to the beach when i got her house a couple of her friends where already there thats when i saw her friend I’ll call her Lea. She is 17 around 5’7 200+ pounds with fat legs and belly. I’m what you would call a chubby chaser I love fat girls my gf is really thick and pretty. Lea is a little uglier and fatter than her but seeing her in a bikini made my dick heat up. Now im confident in myself and me being muscular and slightly above average in dick size (around 7.1) helped with that but at this point i had never actually done anything with a girl. Anyway as we are all getting in the car when im helping Lea put her stuff in I notice her adjusting her bra and at the same time I look i catch a glimpse of her nipple popping out before she quickly puts it back in. She definitely knew I saw cus we both went silent for a moment before we got back to packing. It was awkward for us for a bit but once we got to the beach and I started taking my shirt off and I noticed her looking at my body for a couple seconds before turning away. Looking around at all the girls around me started getting me a little hard so she could see my bulge through my trunks and once we got in the water I decided to push my luck a little further with her and was swimming around “accidentally” feeling up her body. After a while we all said our goodbyes and I dropped my gf and her friends back at her house thats when Lea said she had to go home and asked me if I would drop her off. I looked at my gf and asked if it was cool and she said yes. As we got in the car it was a little awkward for the first few minutes then she dropped the question
“Did you do it with [gfs name] yet?”
My heart started beating fast and I said no neither of us have had sex yet.
She started talking about how she was shocked because “If i had you as my boyfriend i would never let you out the bedroom” and how girls should take care of their bfs so they dont get bored.
That comment definitely got to me cus i felt myself starting to get hard. idk if she noticed but after she said that i felt her hand on my thigh and I was completely bricked at that point.
I felt a little guilty but I was wayyyy too horny at this point to care so I started asking her about her sex life and she told me that she had some experiences before but nothing major. I then told her about when I saw her nipple I thought she had nice tits and she started giggling. When we were going by my neighborhood I mentioned how there was nobody in the house today (Parents on trip). She said I should show her around my house. Once we got there as soon as I closed the door I turn around to see her unlacing her bikini strings and seeing a pair of fat tits drop for the first time was unreal. I brought her to my bed and undressed she said I had a really nice dick mentioning how it would probably be hard for my gf to take it the first time. Once we were both naked and I was fully hard she put me on my back and started licking my cock up and down and popping the cockhead in and out of her lips. She then took a condom from out her bag and started wrapping it down my shaft. She started climbing on top of me and feeling her weight and seeing a huge belly and pair of tits on top of me turned me on so much. She slid it in and started bouncing slowly. It being my first time and having a girl jiggling around on my cock I didn’t last long. Barely 1 minute before I shot probably the biggest load of my life inside the condom and moaned like I never did before. After that I ate her out and brought her home. We had sex a few times after before she left the state and I had to cut off contact as not to have my girl find any of our messages. Now my gf likes to brag how good I am in bed and all I can think about is her fat friend that I used to fuck and those jiggly tits bouncing in my face.