Commitment, natural or artificial flavoring

After my last post we sat down and discussed our issues with each other for a couple hours. There is one thing I have noticed through all my relationships: people in general want commitment that isn't quantifiable. I have lived with a few exes and by that, I mean, moved them in, paid for their food and lifestyle, just about everything, then had them turn around to tell me I wasn't committed to our relationship. They didn't do anything to prove they were committed, in fact, several exes were not, but demand it anyways (especially guys).

It is very odd that the people I have known tend to want me to prove commitment even when I have gone a little overboard. I guess this is something I just don't understand. I can tell them from the depths of my heart that I am committed and do many things to affix them to my life, but they don't want you to move and prove physically that you are with them, they want MORE! They want you to change for them. With me it is usually something that goes against my personal values.

With us:

1. PornIt always has been something I enjoy looking at and getting ideas for the bedroom, but also masturbation. I like masturbating from time to time, nuff said. In my circumstance I believe porn makes me a happier person because I am omnisexual and my interests shift from day to day from men to women to alt genders. What I don't seem to understand is that my current and previous partners have loved porn as well. They also masturbate when I am not around. Yet, my situation is worse because I masturbate when they are around. Why? Because I work longer hours then they have and I have almost no alone time. I should be having sex with them... even if they are busy? Knowing that it hurts their feelings masturbation starts becoming secretive, which makes the situation worse.
2. Open relationship
   This issue is compounding by the fact we can see people separately. No matter how many people we see outside the relationship my partners always seem to worry they are about to be replaced at any moment. It is as if, randomly, there can be someone I wouldn't tell them about and leave them for. I don't have to hide anything but apparently they feel I would... It is a matter of trust and confidence.

Wanting more "commitment", in my mind, is a show that there is a level of distrust and lack of confidence in the fate of our relationship. I analyse what I have done that might be hurting their trust or confidence and ask them about it, but when I haven't done anything wrong then I start to worry. If I have done something wrong I move to fix it.

Every single time I have bent to their whim our relationship dies a little because I become a less happy person. Why don't people get this? Why isn't total commitment on a personal and physical level enough?