Heard [M]y 25 g[F] 28 have sex with her ex 31[M]

Long time lurker here, finally have a juicy story to tell. My gf and I met at a weird time. She broke up with her ex, but she still lives with him. We have been together for 2 years but since the pandemic, its been hard for her to get financial stability so she has had to stay there living with her ex

I used to get really jealous, especially because they live in a studio with only one bed. The more I got jealous, the more I realized just how much I got turned on. My gf is honest to a fault, she will tell me everything even if it hurts me. One day I asked her who the biggest she has ever been with, and she told me that her ex was close to 10 inches and around the size of her arm (she is tiny). I got really aroused, especially because im barely under 7 inches and she struggles with me considering her tiny build.