I feel really left out and a total 3rd wheel! Please help!!?

First, I DO NOT LIKE MY GUY FRIEND. Everyone says that I do but I don't, I like another guy. But recently my guy friend that I've known since kindergarten got a girlfriend (who is also my friend), and I feel super left out. We used to hang out, but now he's always with his girlfriend. Our families used to do lots of stuff together, but now my friend has to invite his girlfriend to all these things, and if she can't come, he doesn't stop texting her. And the 3 of us sometimes carpool (I don't have a say in this) and it's really awkward because they hold hands and whisper to each other like I'm not there. I am truly happy for him and her, they are a perfect couple! But I feel really left out and unappreciated. Can anyone help me? Like in a way of thinking about it? Because I can understand that he really really likes her, but what can I do?