Ask HN: how to leave as a technical co-founder

Approximately 5 years ago I co-founded a business. (We operate in a northern European country; it's the equivalent of an LLC, both of us have a 50% share). I'm "the technical guy", my co-founder takes care of the other half of the work (sales, account management, general management & administration).

The business is fully bootstrapped; it's a B2B (SaaS) business in a nice market with paying customers; our turnover is approximately haf a million euros per year; growth is projected to be approximately 30% over the coming 3 - 5 years at least, at which point we'll reach saturation of the domestic market (but may still expand abroad). In other words: I think it's all pretty successful, and I'm quite proud on what we achieved.

At the same time, I want out. After 5 years of working on the same thing, I'm feeling it's time for me to move on. This is caused by a couple of things:

* I no longer find my work so interesting (rather: I find it boring). This is partially caused by the changing nature of the company (more bugfixes & maintenance than building), and partially by my own desire to make the next move in my career. In particular I'm looking for an environment where I'm surrounded by people that I can actually learn from. I also have a personal project in my head that I really want to devote some time to.

* Unsatisfying in particular is that I feel that most days are spent putting out fires, rather than constructively working on the things that are important in a concentrated manner.

* The constant stress of being responsible for the technical half of the company is taking its toll on me. I sometimes worry that I'm close to a burn out (and my girl friend tells me I should worry about this more, based on my behavior). Whenever I go on holiday (not often, and much more briefly than is common in my country) I feel that things are feeling to pieces in my absence (they often are).

* The failure to build a good development team is a particular disappointment to me.  We burnt through approximately 10 developers in the 5-year period (some of them on the payroll, others on a freelance basis). With about half of them I felt that they were having an actual productivity, rather than creating more bugs than positive . I've never quite experienced the feeling of having built a real team, it often feels much more like baby sitting; this is the opposite of my ideal (which is to give great responsibility to people).

Of course, the lack of a great team and the feeling that things will go awry in my absence also makes it harder for me to leave.

My co-founder knows I want out, I have indicated this to her approximately one year ago. She's not enthusiastic about this prospect, indicating that me leaving is dangerous to the company. She has no ambition to stop herself. In principle, she cannot really stop me from leaving; also: the ownership of half the shares does not imply a legal obligation for me to continue working on the business. (We have an agreement about management based on the amount of work we each do, so that shouldn't be a problem either). I have also indicated that I'm willing to sell my shares if she puts up a fair amount.

At the same time, I feel a moral obligation to her to not abandon ship. Also, I don't want to shoot myself in the foot by abandoning a perfectly good company only for it to crash & burn.

Regarding my co-founder, I feel that her (conscious or unconscious) strategy regarding me is just to sit tight and wait. So far, I have just kept working because I felt the company wasn't ready for me leaving. However, in doing so I don't feel the company has actually become more ready for me to leave. This fits with her goals, because I'm still around.

What's next? I don't know, which is why I'm asking here.

It seems obvious to me that I'll need to come up with some sort of plan to make myself obsolete. But at the same time: this is the part I find hard (I've been trying to do this for the past year or so already, not to much success).

Many thanks in advance for any replies - I've read similar cries for help (though with different circumstances) on HN before and was always positively surprised by the turn-out of the community.