Here is the thing. I knew that big cocks existed. And I had even heard stories about them before, with people in my own life. I had an ex-girlfriend who I am still friends with, and she told me about fucking someone after me who had a superthick cock. But she did not say it was amazing or the best sex ever; it was just an observation. On another occasion this same person told me about her friend, that gave a blow job to a neighbor in college, and his dick was almost too thick for her mouth. It made her friend's jaw sore, instantly. Again, she did not say her friend said it was amazing. It was just a quirky thing: he had a dick too big for blowjobs. Big cocks were out there, just like really tall people, or black people with blue eyes. A kind of curiosity.
But with my wife, I knew it was different. I knew that she liked this big dick, and that it was not just "neat to look at", or a curiosity, it was a big fucking deal to her. She didn't go overseas craving a big cock, she just happened to find one, and became a convert. And I knew that she loved it because she had told me, while she was there and we were Skyping, that she had met somebody, and they were having sex. Of course I asked a little about it, but at the time, did not ask if he had a big dick. She was, of course, reluctant to share much, but again I coerced her, and she shared that she was surprised that each time they had had sex, she had a big orgasm. She attributed it to not having sex for over 9 months -- her last time was with me -- and that she just must be excited to be doing it again. I thought to myself at the time there must be more to it than that, but I let it be.
When she came back, we resumed dating, and having sex. To me, it felt great. Years into our marriage she explained to me how that first time we had sex, after a year of her being away, she expected it to feel how it felt with the other guy, who she had last fucked only a week or so before. But it did not feel that way. She said as soon as I slid in missionary style, she noticed: there was no "tingle" at the opening or her pussy. I just slipped in, easily. And then, when she climbed on top of me, like she had him, it felt different. There was no "electricity" inside. She still felt sort of empty. She knew my dick was inside her, but it just didn't feel how she had grown accustomed to it feeling. Through a lot of effort, and arranging pillows underneath me in a certain way, and with me contorting uncomfortably and her grinding against me, she did come. But without being filled up, it was a mild orgasm. Again, I did not find out about this until years later, after we were married.
As time went on, our sex life changed. She was not into penis in vagina sex as much. Instead, she preferred me to use my mouth on her, and to stick more and more fingers inside of her, pressing hard into the top of her vagina, against (what I hoped was) her g-spot. In her head, when I was eating her out, and pressing her g-spot, she was thinking about getting fucked by a big dick, but she only opened up about this much later. After she had her orgasm, I would enter her, with no resistance, and come in about a minute.