How to deal with a partner who doesn't want to leave his day-job?

I'm a biz dev & marketing guy with a development background and about a year ago I started coding an idea. It took shape and I mentioned it to an ex-colleague / friend. He was extremely unhappy in his day job and was very interested in what I was doing. He's a product manager, but with development experience. So a couple of weeks later I asked him to design & code some web screens. It was all very loose at this stage so no terms were discussed.

Meanwhile, I named & registered the company, made the website and did the marketing etc. on my own.

The product is starting to get a lot of interest, but my "partner" is still wrapped up in his day job and is having problems delivering changes to prepare for the product demos. I'm the guy out there doing the demos.

Long introduction, easy questions :

How can I convince him that without 100% commitment we are probably not going to succeed quickly / at all? He has a wife (no kids) and an expensive apartment and has said that he needs a salary before he can leave his day job. If he doesn't quit should I find a web-developer to make the screens for me and look for a new co-founder?

If / when he does leave, what kind of equity split would be fair? As I mentioned it was my idea & I put the initial work in, but he's a good guy and brings a lot of skills to the table (sales, marketing, product management), so he wouldn't be the web developer for long.

From what you have said, I think that morally (and quite possibly legally too), the two of you are full partners. And you need to face up to this situation together and agree a way forward.

For the immediate future, you need a solution for demos - an important moment of truth for your work. Your partner has product management skills, and this is a product management issue. So tackle that. Look at what you should do and when based on the working pattern you have currently. And look at what would be possible if you brought in some external resource, at a cost that's justifiable against the immediate opportunity.

And when you've got through this step, you'll be in great shape to take a view of the opportunity overall, and ask questions such as, "what's it going to take to turn this into a business that pays two people what they need?"

And when you've taken a long, hard look at that, you can look at what the asymmetry in your current circumstances means, and what the options are going forward.

For what it's worth, you're at a stage every 'moonlight' project that makes progress has to go through. Even if you've talked up front about whether this is something you want to take full-time, and how you'll decide you've reached that point, it's almost never going to be the case that co-founders agree the moment has come.

That's rarely the moment to start making major changes to the team. All your focus right now needs to be on the outside world - your prospective customers.