This is not so much a possibility as an inevitability. Chances are you will fall in love and it will disrupt your life whether you're starting up or doing something else entirely. If you're fortunate, you're new significant other will be a disruptive, yet motivating force. Moving you towards new heights that you had not imagined. But, it's more likely to be a struggle to balance your life's goals with your desire for this new person. Ultimately, you're startup hopes might be replaced by new goals: a family and all that entails.
These things are not mutually exclusive. If you take an all or nothing view, you're being naive. You can have some percentage of a solid relationship and career (whether a startup or something else).
Life is messy. You'll have to decide if your relationship allows you enough time to meet your personal goals and if that even matters. Only you can make this determination.
As for me, I've been with my wife for over 10 years (most of it dating), and... honestly? I think this relationship has had an adverse effect on my goals. I, kind of, think I'd be much more rich and successful had I never met my wife. On the other hand, when she's gone for a weekend, I always think, "I'll get so much done when she's gone"... but, I often end up mired in the "blahs" until she returns. And, honestly...
I think I've slowed down a lot as I've gotten older. I think back on things I accomplished in 3 week coding marathons when I was in college and, while I think I'm a better programmer now... well, I don't repeat those accomplishments. I get more done in less time, but I'm not able to sustain a marathon for multiple weeks. You may be different, or that might be part of getting older.
Ultimately, I've been moderately successful (my business represents the bulk of our income), but not wildly successful. I've come to think less is more... and, I'm happy with that. I doubt I'd be happier single with a larger business and more money.
But that's me...