Aside from the legal aspect, there are two others I think are important.
1) As a founder, you need to do what's best for the company. Whatever that is.
2) You're one of the owners. If you didn't have all the skills required for every aspect, at least you showed up and it got done. You can hire in whatever skills you need, including bringing in a CTO who knows more than you did. Maybe you aren't the right person to run the technical side, etc, but don't be muscled out just because someone is better than you are. Frankly you and the CEO need to stick together - if it's that easy to separate you what stops him from being thrown to the curb when there's a better business guy?
1) As a founder, you need to do what's best for the company. Whatever that is.
2) You're one of the owners. If you didn't have all the skills required for every aspect, at least you showed up and it got done. You can hire in whatever skills you need, including bringing in a CTO who knows more than you did. Maybe you aren't the right person to run the technical side, etc, but don't be muscled out just because someone is better than you are. Frankly you and the CEO need to stick together - if it's that easy to separate you what stops him from being thrown to the curb when there's a better business guy?