Then understand that what both of you should have done is 4 years vesting with 12-month cliff.
With that come to an agreement that since you did two years, you should keep only half of your equity (20%), freeing up the remaining 20% so Jim can acquire better talent.
Long version (Excerpt from a post I wrote):
"These are the legal concepts you can use to protect founders from each other, the company from the founders and founders from a hostile board.
Let's run an Example assuming I'll be your co-founder and the company will grant me 48,000 shares for each of the legal concepts (The number 48,000 was chosen to simply math but does not reflect typical number of shares per founder):
1. Cliff
• If founder stays less than 12 months, no equity.
Example: In this case I receive 0 of my 48,000 shares.
• After 12 months 25% of stock is instantly vested.
Example: In this case I receive 12,000 shares of my 48,000 shares.
2.Vesting
• After the cliff, founder vests 1/36th of granted stock each month.
Example: In this case I receive 1,000 shares a month, on top of my previously earned 12,000 shares after the cliff for a total of 48,000 shares over a total of four years. If I leave in month 24 my total number of shares is 24,000.
3. Acceleration Triggers
• Single trigger: all stock is vested upon change of control or sale of the company.
Example: Let's say Google buys our company in my month 24 of vesting, in order to prevent google from firing me right after the acquisition in order to stop my remaining 24,000 shares from vesting, all my shares accelerate are granted immediately, thus accelerating the vesting
• Double trigger: some stock is vested upon termination without just cause.
Example: This provides a dis-incentive from investors, the board, or a co-founder from firing me if I am not done vesting, in order to free up equity to hire a lot more other people, if I am fired and it's not due to committing a crime like fraud then I will earn some stock, normally 12 months, without having to remain at the company for 12 months."
Even longer version: https://www.linkedin.com/pulse/startup-survival-guide-recrui...