Well, my former friend and I didn't have to grow apart. While I will never actually know why it happened, the break did coincide with him meeting his wife. She came to town with him to meet us once (I had known him for almost 20 years) and after that, his texts to me became fewer and fewer, he stopped acknowledging my birthday despite me acknowledging his, and ultimately never told me he was engaged or married, despite being my best man and informally promising me a spot in his own wedding party. When I found out he was married and I didn't even get invited, I pretty (finally) made the decision that if he considers me out of his life, I might as well consider the same of him. Hurt really badly at the time, but now I don't have that hanging over me anymore.