I used to perform decently in bed until we had a curious threesome with a friend of ours. I was so turned on that she let it happen, and she was so incredibly horny for him, he could practically have her for himself because I was already edging when they were still merely kissing. When it was my turn, I came prematurely, half, and again once I was in her very warm pussy. I was unable to copulate or I'd cum in full. I didn't want that yet because he hadn't come yet. So I pulled out. I had been in her for, what?, ten seconds and had been unable to do anything. He then took my place and fucked her through the mattress. He even took her a second time that night. It was not a threesome, but the night that I became a cuckold. I never properly recovered from surrendering my confidence to him that night, which is fine.