Questions like this are normal for somebody just beginning to think about swinging. I think some of these posts were too harsh and condescending. People come here to learn things and alleviate their petty fears or insecurities. Most of us had them at some point.
tamyou, Likeminds gave good advice. I would suggest you keep reading the threads before you go to your wife. You will find out in time if you can get over your concerns.
This should be about sexual pleasure as a couple, for you AND your wife. So if a bigger dick does that then you should be glad for her. Do you want to do this and have her not have a great time?
Good luck and don't be afraid to ask questions, any question.
BTW-welcome to the SB.