Am I my boyfriend's second choice? Is he getting bored of me?

I've been dating my boyfriend how 1 year & 2 months. I recently found out in the beginning of us talking seriously he was also talking to another girl about being serious at the same time. They end up dropping it because he wanted to be more than friends but she didn't want to. They got into a big aruguement then the next day he apologize & said he can't drop her or ignore her but they ended up because she repeatly kept saying they shouldn't talk cause it's not going anywhere. Then a couple months later me and my boyfriend became official. Now it seems like he lost interest in me because he's not the same romantic guy he was back then. He doesn't show he cares, love or appreciate everything I do for him. I am always there for him but when I need him he disappears. Everytime I talk to him about this or how I feel he ends up getting mad and ignores me and will not talk to for a day if I'm still upset about it. But he still tells me he still wants to be with him & he does love me. It's just how he "is". He's way too comfortable with me. He knows I'm not going anywhere, so he takes me for granted. He still doesn't know I know about that one girl, I don't know if I should bring it up because it sucks knowing I was the second choice. & now he seems like he's bored of me.
Am I my boyfriend's second choice? Is he getting bored of me?
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