Is it rude to ask if I'm invited to a wedding?

So babe and I have been dating since 2012 and engaged in 2015. His close frat brothers (3) are getting married right after ours (2 literally within a week and the other in September). They know we are together and have been invited to our event but some how all the invites have only been address to him and specifically noted 1 seat has been reserved for him. Now I don't know if its just me taking notes from this forum that if you know someone is a couple that you should invite them together. I do see they noted adults only, which is fine but I hope that is not the reason that they only invited him since we have a son. Or that they were going the cheap way and not wanting to invite us as a couple. I don't want to be the person that cross out their 1 seat and put in 2 seats and they get mad but hey..lol