Am I being selfish or too close minded?

Bri

Long story short, my dad died a few years back and my mom for a long time wasn’t looking for anyone else. Now though, she’s dating her ex husband that was just a dead beat dad to my sister and brother (that’s their biological dad btw). He came back to her after breaking it off with his wife not too long ago and now they are dating. I don’t really like the guy because he just drinks all day and doesn’t have a job, but for some reason my mom loves him. My dad was a great man btw, he was a hard worker and always did everything in his power to give me the best life and my mom and my dad never fought once in their entire lives, they were soul mates.

Anyways, my moms ex husband comes back into the picture and now all of a sudden my sister and brother are calling him dad, even though my dad raised them since they were only children when their biological dad wasn’t there, he was just out drinking or cheating on my mom. The little thing that really upsets me is that when my mom talks to my sister and brother she’ll refer to him as dad and it hust reallly upsets me because I feel like my sister and brother gained a dad while I lost mine.

What I wanna ask is am I being too selfish for getting so upset that they have their dad back and I don’t? I feel like I’m not in the family anymore because whenever my mom wants to do something fun she always takes out my sister, brother and “their dad”. I don’t feel like I’m in the family anymore and it’s reallystarting to bother me.