Time is changing for you very soon starting February 2023. Last 7 years of learnings will synthesise into some new way forward and new beginnings. In that context, if a fitness studio is what you want to start with, its a good decision.
Female partner and being friends already is also good for your association. Time untill next 2 years till beginning of 2025 is fine for the association.
Partnership concerns and issues will arise after that, you need to be careful about those while planning.
Rahu-Mercury Dasha and end of sadesati is a good segway to start a new initiative. Yogakarka venus is 10th lord, and income lord is Mars sitting in 5th aspecting 8th and 11th house, so fitness studio is a domain where results will be obtained.
Rahu-Ketu dasha will bring partnership dissolution or conflicts. D-9 has 7th lord Saturn in 5th house in mars rashi indicating good prospects with business.