It is unfortunate, but split-ups seem to happen somewhat frequently based on my unscientific survey and personal observations. I think the core of the problem is when founding teams don’t plan for a potential break-up at the start. It may seem pessimistic to go into business together with this mindset, but I feel it shows professional maturity. So, talk with your business advisors and lawyer about what would happen if your team lost one of the founders in the first year or two. Then, tweak your incorporation documents with your lawyer to get to something the founding team agrees is fair.