I've been recruited by a startup as a senior architect for their platform, working directly under the CTO in a small (<10) science & engineering team. I recently had a stroke of luck and it looks like I've got seed money coming for one of my side projects, enough money to focus on it full time.

The CTO recruited me directly based off of a recommendation. I'd be an integral part of building and scaling out their platform, and they don't expect to hire too many more engineers in the near term. I don't want to be a home wrecker here. Do I tell the CTO that there is a 50% chance I'm gone in a month?