That's all possible. But the problem is that he wants this style of relationship and continually pushes for it. I have offered many times to take a break, to stop, to not seek out anyone else without him. But he has told me every time that he doesn't want me to do that. He usually explains that he feels happy to know that I'm enjoying myself and other women and is happy when he can be a part of that as well.
We live together, we spend a lot of time together and enjoy cuddling near the fire, reading and other activities. I've tried setting up a "just us" date night, but I can't really 'force' that one. The problem from my point of view is that he gets in these moods where he starts to think no one likes him, that he's unattractive, etc where he will ignore everything around him. We were sitting on a bench with some friends of ours at an event I casually suggested a scene, with both my partner and I, she responded excitedly and my partner was stone-faced. After complaining all afternoon how bored he was, how I wasn't flirting enough with girls to bring them back to us, how I should be doing more. Obviously the scene didn't happen because I was waiting for my partner to respond and all he did was grunt. Later when I discussed the situation with him and how odd it was (especially after he had told me I SHOULD pursue that specific girl), he told me that he hadn't even understood the situation.
But maybe if I explain a bit more how we got into BDSM. He was the one pursuing and wanting to go to munches and parties and things. He continually encouraged and pushed me to go, finally I said sure and we went. He encouraged me to go flirt with other girls. We went to a rope skills party and he tied me up, while encouraging me to go flirt with the other girl being tied up. He would continually push me to flirt and kiss other girls. He once (the 4 or 5th happy hour we went to) held me down during a happy hour and encouraged some friends of ours (some nice girls we had just met) to molest me a bit. I don't feel like my behavior is out of the blue, he continually encouraged the behavior and sometimes it felt like he was using me as bait to get other girls interested.
Once I discussed the issue with him, he realized his behavior wasn't very nice and we started together dating a girl whom we have a pretty good emotional connection to and truly liked us both.
When I say "force", I mean that it often feels like I'm pulling teeth when I ask for him to have a conversation about what he wants out of this. He never gives me a definitive answer. I would be happy to stop doing any of this if thats what he wanted me to do, but what he has seemed to express in actions and words before we started talking is that he wanted me to go off trapping and catching girls for him.