this is a hard call i think, i kind of think the word ultimatum, sounds a little or controlling, but setting deadlines is kind of a good idea i think, but what do i know about it. i think that it may help if you could have a conversation with him explaining how you feel and how long you are will to wait, may be set a few boundaries, you seem to be doing pretty good without his income, and thats a plus, at least you have a plan just in case things don't work the way you plan them. i do think that the decision is yours, though