This has happened to me in the past. Best Friends from childhood, stayed at my house when things were bad in his family, for months. no one ever asked his family for a dime, what are friends for right? All those years helping him through the toughest subjects in school, I gave up sports and a part time job to coach him when there were no one else. I was happy and excited for him when he met the girl of his dreams and loaned him the money for the ring (haven't been paid back yet for it, and it's been years over three years...). When it came time for the invitations to be formatted and mailed, our family did everything and also picked up the tab. Then he announced who The Best Man was, and it was someone he'd only known for the past two years, a regular from the bar that he owed money to. I sat in the back row with a couple of other people who had supported his causes over the years and tried to put on a brave face. I wasn't asked to give a speech, nor was my family, who'd practically raised him when he had no where to go or a place to live, were shuttled to an outside table, near the restrooms. Our gifts were never acknowledged and I know my parents put a sizeable sum of money into the envelope that he took with only a nod and a big smile, not even a thank you spoken.
We never heard from him after he and his new bride got back from their honeymoon, only when he needed a reference and a consigner for an expensive SUV. For both requests, there was a polite 'No' and when he said, "Why not?" in a very rude tone of voice, I brought up the unpaid 'loan' for the wedding ring and he tried to turn things around with a "You said it was a gift!!!" which I never did, and I have his signed, dated, notarized loan documents, witnessed and formatted by my parents, to remind him in the future when I take his sorry ingrate of an ass to small claims court. Some people will take advantage of a person because they simply don't care after they have used them. I'm still open with all of our friends, and my now former Best Friend only bad mouthed me to a few of them and they told him off royally. Apparently his new wife isn't too happy with him, he still doesn't have a job since getting married and spends much of his time at the bar where he met his Best Man. Not sure if that guy has ever been paid back. Be careful who you open your heart, your door and your wallets to. I don't miss the friendship at all, and I still help people whenever I can :)