How Comfortable Are You With Adding Others Joining?

I personally would like to try to explore with a couple. I like being with a girl... and I love sharing my guy, but I will admit... It would be a lot more fun flirting with another guy or at least having a guy eat me out while I enjoy watching my guy. Sometimes I leave the room for a moment while he's fucking another girl. I am either tired and not stimulated enough and take a break... or I let them have their fun. If there was another guy involved... I can see myself staying more active during play.

But... I know my guy is not open to another guy joining in. I would like someone I can trust... someone who is okay with my guy being there and also someone I can handle as well and who is aware of my "tight pussy" condition.  I don't necessarily want a stranger in my bed. I want someone I and my partner can trust as well....

Here's the thing though... How do I convince my significant other that I want to have sex/oral sex with another man but it has nothing to do with him or his abilities etc... I just would like to experience what he is a bit... I mean... Ive let him sleep with 3 other women since starting this. And at least 4x without me being a part of any of it.... in the middle of a work day while I am at work...

I know I am definitely the "freakier" one out of the two of us... so this is why I am questionable to how I can get him to be more open etc... He has stated that he might be okay one day with another guy but he hasso many rules on top of that..  like, no kissing... REALLY!??!... Or.. I cant give Oral to another guy... Thats my favorite.. I would looove to have a threesome where I go down on a huge Cock and he fucks me from behind.... that is my ultimate MFM Threesome scenario.  

Any suggestions on how to be open and have a conversation about this with a male in the couple....
How to talk about MFFM and MFM