This article was of course a distilled version of a much longer conversation. The uneven equity split that causes problems is usually along the lines of 75% vs. 25%-- or worse, when one founder gets 10% or less. We see this happen quite often (and advise against it if we're not too late). The founder with 10% often becomes resentful and doesn't feel properly incentivized when he/she is working just as hard as the founder with 85%. A startup is so much about execution-- usually over a long period of time that the argument of "it was my idea" isn't very compelling. (60/40 is usually totally reasonable though, especially in a situation like yours.)