Am I wrong for this?

Am I wrong for this...
So my fiancé is in the army, he's currently doing basic training boot camp... I see him in 3 more months which is when we're getting married.. Anyways, he has a family now.. Which is me and his son.. Yesterday I received a call from him and only lasted 60 seconds.. Sure I'm glad I got to hear his voice and for him to tell me he loves us.. But his MOM was the one he called first and chatted with longer.. 
I feel like his mom is always going to be the first and his family (me and his son) will be last.. 
I'm thinking about writing him a letter.. And telling him that he has a family now, I understand his mom is his mom, she gave him life, but he's an adult now and what he needs is love from a women now... Something HIS MOTHER WONT BE ABLE TO GIVE HIM. He has me and his newborn son now. 
He always has to go to his mom.. He always needs his mom.. It's just something I'm getting tired of... Then his mom rubbing it in my face that she'll be seeing him on his graduation... (I can't see him.. Purpose reasons why I can't).. 
I'm just tired of his mom ALWAYS be the one on his mind first THEN HIS OWN FAMILY. He gets a chance to call and his mom comes first.. That's bullshit! She writes to him.. He can write to her back.. But he has a damn soon to be wife and his baby boy here waiting for him.. And to find out he's always putting his mother first then us just gets me thinking.. Are we even in his mind while he's over there or is his mother more in his mind then US! 😥