My husband has been patient through years of on-call duty and pages at all hours of day, night and weekends. He's been patient through all night maintenance duties and when I'm away for conferences or customer visits few times a year.
I've been patient when his company adapted this agile practice that means a release until 4am every Wednesday.
One thing I'm wondering about is the "get involved" advice: I'm a pretty mean developer, but I work in languages and environments that are very different from what my husband is working on. Whenever I try to discuss his work problems, I end up asking lots of wrong questions and generally annoying him. There is very little I can do to actually help him work on problems. Thats with me having 15 years of coding experience.
There is simply no way a girlfriend who is just learning to code can help her startup SO work on his projects.