Definitely do not sell / give away that shareholding.
It may well become 40$ of nothing, but it could also become 3% of nothing or almost-nothing, and the co-founder will have been paying himself a return when the company gets revenue.
I suspect there may be other personal/personality issues here and he may well like the idea of hacking alone on this, now that it appears to be viable. However, he has an agreement with you, and you made commitment, put in effort too. That's why you have a shareholding.
Do not just give that up, unless he makes it worth your while 'now'.
I suspect there may be other personal/personality issues here and he may well like the idea of hacking alone on this, now that it appears to be viable. However, he has an agreement with you, and you made commitment, put in effort too. That's why you have a shareholding.
Do not just give that up, unless he makes it worth your while 'now'.