there are many issues that you're facing now... but it may be simplified if dealt smartly and with all integrity ... first of all you took too long to implement/execute your idea - so now you're in trouble (internal and external).
anyway lets resolve the internal issue first. You need to find out what your partners really want, chances are they want/need something else than what it looks like from outside, find out what will motivate them to stay with your project?, also it is not clear whether they prefer to quit or they prefer to change the concept, may be they want to quit because you're not flexible enough to listen to them and change the concept - you need to really listen to them and think rationally (not emotionally) whether changing the concept will benefit all, try to create a win-win situation for all. last option is to let them go (because if they are not motivated enough then it won't produce the desired result) without burning the relationship, find the replacement at the earliest. If they are united and want to close the company then find out the legal way to hold on to the intellectual property at the minimum cost to you....
if they are your true friends then they should not give you hard-time in exploring either options. If you really love your project then you have to be very firm though in a polite way so that they can figure it out that you're really serious to pursue your ambition and nothing can change your route (with or without their help) - may be they will change their mind after seeing your determination.
1- Determination is what kept me moving all a long. I could've easily forgot about it, years ago.
2- This is what'll be trying to do.
3- They don't want to leave? What if they want to force a change?
4- I have my day job that I need to pay for my project.
if they force for the change that you you disagree in totality then there is no other way then to quit and go on your own ... if you're busy with your day job then you need to find someone who is not that busy or who is available full-time for stock options
EDIT: somehow you have to make an agreement with your partners (if possible do it legally) that if they decide to quit or if your partnership is dissolved then IP (code) remains with you (because originally the idea was yours) and in the future they cant do something similar either, i dont know whether it is completely enforceable legally but i dont think if any company (say goolge or yahoo or MS) will let me pursue the idea on my own that was originally not mine - so in the same way you can have an agreement or contract with your partners too.
anyway lets resolve the internal issue first. You need to find out what your partners really want, chances are they want/need something else than what it looks like from outside, find out what will motivate them to stay with your project?, also it is not clear whether they prefer to quit or they prefer to change the concept, may be they want to quit because you're not flexible enough to listen to them and change the concept - you need to really listen to them and think rationally (not emotionally) whether changing the concept will benefit all, try to create a win-win situation for all. last option is to let them go (because if they are not motivated enough then it won't produce the desired result) without burning the relationship, find the replacement at the earliest. If they are united and want to close the company then find out the legal way to hold on to the intellectual property at the minimum cost to you....
if they are your true friends then they should not give you hard-time in exploring either options. If you really love your project then you have to be very firm though in a polite way so that they can figure it out that you're really serious to pursue your ambition and nothing can change your route (with or without their help) - may be they will change their mind after seeing your determination.