Why do people keep asking my girlfriend how she ended up with a guy like me?

I don't like bragging but my girlfriend is kind of attractive. I don't think I'm Tom Cruise in looks or anything but I didn't think I was as bad before I noticed that girls especially have been asking my girlfriend how she ended up with a guy like me. My girlfriend and I have been together for only 4 months but we got together because I was there for her when she was going through tough times. I also treat her like a queen and she treats me with the same love and affection in return. We're close. She says herself that I was there for her and that's what counts for her. Are girls asking her this because they think she can do much better?