A very difficult situation - thank you coming here and sharing it with us. Things like this are very good to help others see that their situation isn't the only one like this.
You are not the first person I have heard of whose partner said it was ok for them to be with another, as long as it was only sex, and then been surprised and upset when sex and love cannot be separated.
This is definitely a case of "be careful what you wish for" - personal growth, and encouraging a partner to discover themselves is an important part of good, healthy relationships, in my opinion, but sometimes it can mean that incompatibilities between folks can surface.
It is sounding very much like you are poly in your wiring - you don't see the contradiction in loving more than one person and being in full relationships with them. He is ok with exploring sexuality, but can't handle it when there is love involved - this is (from my limited understanding) more typical of a swinger mindset.
I think that it is great that you have found this part of yourself that you didn't know about. It may end up meaning that the two of you aren't compatible for a relationship. I don't see why you should be the one that has to sacrifice your personal growth because he can't handle the way you have grown, after encouraging it so hard.
Please feel free to talk more about what is going on, and your thoughts. My only request would be that you put a little more white-space on your future posts - it would make them easier to read.