People should really get their experimenting out of the way before they get married or even settle down with a bf/gf.
With an ex bf (ex fiance actually), we tried the whole 3some thing. He always wanted to have one with two other girls and I was curious about it as well.
The day came where we were going to have one. The girl we met, we all had gotten tested together (just to make sure no one had anything). We all went to my fiance's house and went into the bedroom. Well, they started practically pouncing on each other, undressing each other and leaving me out of the equation. I undressed myself, waiting for my fiance ya know. Well, they pretty much ignored me and started having sex with each other! I just stood there in shock. I couldn't believe my eyes. I felt like I was just watching him cheat on me. I started talking, they ignored me. I started to yell after they were ignoring me, still ignored me. So what did I do? I pulled the little prostitute off of him and told her to get the f*ck out.
They were both yelling at me, she just stood there naked. I hurried up and got my clothes back on. She was still standing there naked, and kept trying to go over to the bed where my fiance was. I pushed her back once again. I ended up taking all of her clothes, shoes, and purse and threw it outside. Then I pushed her outside and locked the door. Then my fiance was pissed off and was yelling at me more. So I told him that I just basically stood there watching him cheat on me. He tried apologizing and everything. I later forgave him. Then he said that we should try it once more. I told him there's no way i'm ever going to do that again. I'm not a jealous person, never have been, but that night, I got super jealous (obviously).
Well, a couple months down the road, I find out that he has been having sex with that girl after the "3some". I go over to his house and see a familiar car in the driveway, I walk in (had a key to his place), he's no where to be found. I go to his bedroom and the door is shut and I hear noises. I walk in and see him and her having sex. Again I pull her off of him, but beat the crap out of her this time. I take off my ring and throw it out the window and tell him to never call me again.
I now don't know how anyone in their right mind, that seriously loves someone, would want to bring another person into their relationship. All it does is cause more damage and you lose the love you have for one another. Bringing another woman into the relationship is just going to make him think it's ok to have sex with other women when you're not around.
People who choose not to bring another person into their relationship doesn't mean they're insecure. I believe that when you're with a person, you are only with them, no sex with others. When you're married and you do that, you're breaking your vows that you gave on your wedding day, making your marriage worthless and fall apart.