Alternative Approach to Issuing Ultimatums

Ultimatum, or; last offer, final proposal, last chance, demand or warning. I don't know about you, but most people get angry and defensive when given an ultimatum.
Now here's a better way to handle it....Calmly explain your needs and expectations. Use nice but straight-foward intelligent language.
So, instead of saying "There better be a ring on my finger by year's end or I'm otta here."...Say
"I love what we have and I enjoy every moment we spend together. But, I'm not sure what your plans are for us in the future. I want you to know that I'm no longer interested in an open ended dating just for fun relationship. I'm looking for someone I can share my life with, get married and have children. I want to start a dialogue with you so I know where you stand. So, I'll be clear, if we're not on the same page, I'm going to consider dating other people who are open to the idea of settling down."
It's not an ultimatum, but it a clear assertion of your intentions . It's a statement of your true feelings that are direct and to the point. In Summary...no threats and no beating around the bush.