What Is It?

What is it about imagining my wife enjoying a very large size penis that gives me an erection.
About 3 years ago, my wife finally hooked up with a guy who measured 25cm in length and was 20+cm around. Ever since that night I can't stop thinking about how she must have felt deep inside.
He had been trying to entice her for a long time, and after much discussion bewtween my wife and myself, we decided that it would be a great opportunity for both of us, as I had always enjoyed stories about wives cheating with much larger cocks and my wife had always wanted to try one that large. She had previously had a penis about 18cm in length.
She has told me he was very good in terms of technique and also came in large volumes, and it really excites me to think about it.
Everytime I make love to my wife, all she has to do is gently reming me of her night with her stud and I almost immediately orgasm.
Is this a normal reaction to have about one's wife?

Well, it certainly isn't uncommon. You see ads with couples looking for this frequently, and I have been privileged to be involved in a few situations like this, usually set up by the husband, where they were looking for a hung guy for his wife and I fit the bill, so to speak. You are not alone for sure.

As bigjpgh says it's not uncommon. I too play host to a few couples from time to time and i find that if I've had sex with his wife and he isn't there then the fantasy just grows as it's his mind that races and makes the though of my cock entering her possibly bigger than it is.

I also have found that these are the guys that want to be close during the sex when we all finally meet so he can be close the the action to finally visualise his fantasy.

I don't see anything wrong with it but you do have to think about is that is it the fact that your wive took a big cock that gets you off , or the mental visualisation of your wife taking a big cock.

Not uncommon at all, I have heard a lot about men that love seeing their women with hung and powerful stallions.

That would be a turn off for me, though.

It's not quite the same thing, but I think it's hot as hell to see a hung guy fuck my husband. Of course, I think I'd rather be the one getting fucked, but it's good either way. That's one great thing about being gay - we can both enjoy the same tricks in the same way.

I guess the question is what is normal and who gets to define it?

If it works for the two of you, involves only consenting adults, and no one is being hurt, does it really matter if it is "normal" or not?

To answer your question, yeah I've heard of this. I wouldn't say it is common, but it really seems to work for some couples. It usually involves the husband being somewhat self-conscious size wise (even if he doesn't need to be) and he ends up using it as a fantasy. Lerotic defined two of the fantasies that seem to come from this. There may be more. I'm not sure.

Personally, I don't really get it. Threesomes I understand. But I suppose it doesn't really matter. As long as it works for you and your wife, I suppose that's all that matters. Best of luck to you.