Marriage is a sacred thing and a commitment between 2 people and it should stay within those bounds. It isn't to be taken lightly as many people do now. When you have children (natural or adopted) you commit to taking care of them for 18+ years and you literally have no idea how they are going to turn out. If you decide you can't deal with it you can't abandon your children. You pick your wife and then decide you want to have other people? ("you" in general) One of those most important things about marriage is that 2 people are attached intimately deeper than with anyone else. I just see adding others inside of your marriage as a complication, a breech of trust and no good can ultimately come of it. I wouldn't go into it just to prove how "progressive" I was. If you don't like being with the person you're with, don't get married to them and construct a whole life only to have it come down, or just let them go if things are so bad that you just can't contain yourself.

So no sir, you aren't wrong for not feeling comfortable with it.