In hindsight (and if I could do it again) I would grow the business slower and manage the growth rate. What I didn't realize was that with increase in growth, there is also an increase needed in capital requirements in order to support that growth.
How many hours do you work?
When I first started I was probably working about 80 hour per week (from morning to night, with breaks in between). Now that the business has matured and I've built a team around it, I generally work about 60 hours a week.
Is it hard to have a relationship when you are launching a start-up?
When I started the business I was not in a relationship at the time, and I think being single (and only accountable to myself) helped tremendously because I was able to focus 100 percent of my daily attention on creating, nurturing and growing the business.
Overall I think having a relationship and starting a business can very likely clash, because of the time commitment and energy required to start a business (which may take away from your significant other), but I also think the level to which it affects comes down to the couple and how well they understand, communicate, and are on the same page with each other.