If the business is already thriving, bringing in good money, the answer is easy. I wouldn't. If I have signed contract for job that pays 250k to 7 figures, I wouldn't. If it is a startup that's promising, I would give it a shot for another year before giving my final answer.
People fall in and out of love everyday. All it takes is spending quality time with someone. All of a sudden you'll start looking at each other differently. You cannot guarantee you or your partner won't meet someone else even if you live together.
Plus if you make a lot of money but still miss your ex, you can join them maybe 2 twice a year.
When it comes to romantic relationships vs money, choose money. You'll be surprised how wide your dating pool is and how beautiful a romance can be when you have a lot of money.