One comment that I've seen made is that running a startup is a lot like being in love. So a related question is whether, if you're not in love with someone, you

One comment that I've seen made is that running a startup is a lot like being in love. So a related question is whether, if you're not in love with someone, you're more likely to totally obsess over your startup (and whether that changes your chances of success)... But as to the original question, it varies so much on who you're in a relationship with, what you're working on, and how the two fit together. From a startup PoV, is he always demanding you 'stop work' to pay him attention? Is he intrusive rather than supportive? Is he able to deal with you having a spontaneous, flexible schedule that might change at a minute's notice? Is he OK with the fact you don't earn any money? Is he going to scream if you decide you have to move to a different city to succeed? Does he yell at you for getting up in the middle of the night and furiously typing? I could go on all day, and mostly from experience. ;-)