When I talk to her, or tell him about what's going on. Is he lying to me or himself?

He is lying to himself to protect your feelings.

It sounds like he is NOT OK with it, but is forcing himself to be OK with it for your sake.

You need to decide what is best for you. If he is having a hard time with an open relationship, decide if you want to leave him, or stay with him and be monagomus (or however its spelled lol)

Good luck :)

Due to posting restrictions on the Adult Sexuality board, how old are you?

I'm 26, so no worries there.

I think things are better, or at least moving forward in a respectful way and happy.
I talked in depth with a poly-amourus friend of mine for some experienced advice. I took some time to check in with my boyfriend, and love on him, shower him with affection, etc... He loves that :)
I also invited my lady friend to join the two of us, I think him participating will make him feel more comfortable. He and I talked openly about that, and he's happy about the idea, and excited.
I think we will just take it one day at a time and see how this goes. If something changes, and this is not OK, or heor I feel uncomfortable or distressed about it, I will check in and move forward from there.
I am fully willing to be monogamous too, I love this man and I would like to spend a long time with him.

I am glad you talked to him. Too often couples just fight rather than talk.

I wish you luck. I'm glad he is willing to try it out for himself.

I am glad you are communicating, but I am hoping you are doing more planning for the threesome than it sounds.

Make certain that everyone knows what is going on and what is expected before you get into bed. I am concerned that your boyfriend may be thinking about fantasies and reality may cause more problems.

Good luck and may everything work out for the best.

Our first attempt at a threesome could have definitely been better planned. As it turns out, my partner was a bit insecure for joining in when he wanted to and the participation wasn't smooth. Nor was communication in the moment. However, today we had a deep discusion about the need for better communication, and inclusion. As well as the possible roots of insecurities, and how we can work together to help him work through his own insecurities. This is not an issolated incident of frustration through insecurity for him.
I wish that we had planned it better, and talked more throughout the encounter, but it has presented us with this amazing opportunity for growth through complexity. We are going to have a special date today to strengthen our bonds, and check in more efficiently in the future.

We have really good communication, I feel really blessed. I'm not sure trying to figure this out would work otherwise.
We did some more talking about it, and I found out that it was fun for him for the most part. He still likes the idea and is willing to try it again. (his idea) Our agreement was that if he needs to say something or needs to feel more included he has to say something, or come try to play. And I will try to be more verbal, and check in more often. So as long as our play partner is still happy to play (have to chat more w/ her) were good to go. I think this has helped a lot.

This is really good advise, I will make sure we do this next time, and check in during as well. I have been hearing from people I know who also play with others, that things can change in an instant and so it's important to keep checking in.