Is Marketing co-founder a must for tech founder?

Hello lovely people.
I am building a Client management software for Agency founders. Through my years as a software Architect I have worked closely with the Product managers and the pre-sales team and learned the art of Product mindset and putting myself in the target audience shoes. I have a list of cool features in the pipeline.

• Single dashboard to manage multiple client projects.
• In-built client communication channel
• Different workflows for different client projects
• Integrated cloud storage to store, edit, collaborate on digital files
• Track staff attendance and bandwidth
• Support for invoices generation and tracking expenses/cashflow

Coming from a pure tech background it is easier to get into lets-build-it-and-they-will-come mindset. But as a true believer in lean startup model, I want first to interview a few prospects before building actual product.

I have more than a decade worth of experience coding solid tech stuff, but what I lack is tangible exposure to Sales and Marketing. There are dozens of best-and-cheap ways on the internet to get leads to signup for the waitlist. However sometimes I just feel I can't bring myself to do it and find comfort in building the Product. The other problem I run into often is with the lack of accountability partner, how to balance between time for side project and time for my day job and family. I am not sure if anyone else has ever felt this way.

I would love to hear your thoughts on this.

PS: here's the landing page jetdesk.io