if you know you can't live like that
you might have to leave him. Most people make the mistake of getting the ball rolling first, and then letting their SO know after the fact, if you haven't taken any steps to start seeing other people you have absolutely nothing to feel guilty about.
I also wouldn't assume just yet that he will never be accepting of non-monogamy as I believe not many spouses take the first talks well, especially if the first talk is reveals something wherein they feel betrayed. Not having that working against you is a good thing. I believe how you bring it up (the words you choose to discuss the topic) and the events that lead up to the talk are very important. It's hard for me to believe that any person in a committed relationship has never had a fleeting thought about sex with another person. So maybe ask him if he is honestly claiming that because for some people (actually a lot of people) denial is much easier and more convenient than dealing with the truth. If he can't at least admit that he fantasizes about it sometimes but it's not something he could ever do, then at least you know that continued talks won't be a waste of time.
There is no point in talking with someone in denial, it will likely start an argument and if he is coming from a place of denial, logic and reason aren't going to phase him. If you read around the boards you'll see denial lets people avoid any and all the unpleasant parts of a relationship and it happens in both monogamy and non-monogamy. Some non-monogamists require it to see other people, most often in the form of "don't ask, don't tell" and the second most popular is an inability to meet your lover's SO.
It may be time for a serious talk, because at this point with him being devastated when you haven't done anything but share how you feel with all your cards on the table and nothing hidden (which you should proud of yourself for being able to do) and his reaction in turn leaves you feeling horrible, then somethings got to give.
Keep in mind though, what you are experiencing is normal for relationships in general. That "itch" is inevitable and sometimes a person only figures out what they really want, until after they lose their spouse. If that's the case with you, maybe spending a couple months separated would give you clarity. There is a big difference between feeling like you can't be with someone and actually not being with them. And the world doesn't end or begin with either monogamy or poly.
Last edited by Dirtclustit; 06-08-2013 at 10:12 AM.