Need career advice! Stuck between two jobs. (originally posted in r/work).

Note: I did post this in r/work but I figured fellow MUAs might be able to help me more with my dilemma.

I've been working as a freelance makeup artist in film/fashion for over three years now. I'm gaining a lot of notoriety, but that really doesn't pay my bills until I get into a union or agency. I've been trying to find a steady part time job, still in my field, while gaining more experience working on independent productions and creative shoots to add to my portfolio needed to apply for the film union. Suffice to say after nearly two years of job interviews, I've gotten really used to rejection. Finally after so many interview busts, I just received a call back for a salon makeup job that is part time, but minimum wage to start. This would have been amazing if I was not in the running to be a key MUA working on a high profile independent production with a very known director, that would need me for at least a month. And being that I told the salon manager I would be available ASAP, I'm having a bit of a career dilemma. While it would be a relief to finally have a paying job in my field, I know it's not my passion. And while it would be amazing to be the key artist for this film and would do wonders for my resume, I don't want to put myself and my SO still living pay cheque to pay cheque for god knows how long.
I did talk to my SO about my situation and he ultimately said I need to do the film, but I hate the fact that he keeps supporting me while I'm trying to focus on getting my film career off the ground. I feel guilty every time I leave to go to a non or low paying gig and whenever my interviews for pt work go nowhere. He's been so patient with me over the years that I'm leaning more towards taking the salon job just so we can sit comfortably for awhile, but I know I'll regret not taking this film job.

Help me MUAS. You're my only hope!

*UPDATE! Just had my second interview with the salon, where she did offer me the PT position. I took KiraOsteo's advice and just explained that a temporary job opened up way before they called back, and that while I want to still work there, my start date will be in the fall instead of right away. She was totally fine with it, and said she is willing to still offer me the position, when I'm done with the film. In the mean time, she's offered a few on-call shifts in the salon for the weekends until I leave for the film(which I'm still waiting to hear back from, but it's looking good). Thank you girls, and KiraOsteo for your advice. I will update about the status of the film gig!