Sara- I haven't followed your sitch from the beginning, but I will weigh in anyway.
Before giving anyone an ultimatum, make sure that you are prepared for the worst answer. Instead of telling him that you want your marriage to work, try something similar to "I know I am going to have a great life. I would love for you to be a part of my life, but if you choose not to, that will be your decision"
Also, you say that you will get better once he makes his decision. This is giving him all of the control in the relationship. YOU control your own happiness. YOU control your PMA or lack there of. The sooner you take control of this, the better.
Good luck
MC
Me: 44 S: 17 and 7 Final-6-13-08 I once went to a psychic who told me I would soon feel cheated......