I keep being people's first boyfriend

Title says it all really. I'm 24(m), and have been in 4 relationships. Aside from my first boyfriend, I was the "first boyfriend" in all the subsequent relationships.Being someone's "first" isn't something that I get off on or anything- it certainly doesn't make a person more attractive to me (or less).In all the cases, I haven't been the first person they've had sex with, only their first relationship. I don't know what this means, or if this is a good or a bad thing? It's just a trend I've noticed, and it worries me a bit- I'd like to eventually find someone to settle down with, and am aware that most people don't usually end up with their first partner being their life partner.Advice and/or perspectives much appreciated.