My online daddy dom developed another dom/sub dynamic without me knowing

Basically what the title says. Been in a ddlg online relationship for about a year. Although we aren't exclusive in the sense that we both date other people casually (we hope to eventually meet in person) ... I was under the impression I was his only sub as we talk every single night and I'm his first little. I found out recently that he met someone in real life (much younger than me which makes me more insecure) - and for about a month had a dynamic. I had no idea. He constantly told me he has no interest in others and only wanted me. I honestly don't even really date anymore cause I'm hoping we can meet soon. Anyway... I was really sad. This was my first ddlg or even d/s relationship in general. Am I being selfish or are my feelings valid ? He constantly told me he loved me every night . I just didn't expect someone else being his sub as well. Probably a rookie mistake from me ...