I know this is kinda long-winded but this hit on a major point of contention I've battled with way too many times in the past.
Before my (now present) wife and I started dating, I explained to her very clearly on the first date that music and her happiness are top priorities (not the fringe things that inevitably come along with playing live shows) and she understood clearly. 5 years later, we're happily married (with mortgage and bills, I've down-shifted music to a slightly different priority now) and she has been very supportive of me without meddling in band functions. Most of her acceptance of my musical life has alot to do with how I've dealt with OUR priorities. Actions always speak louder than words.
Alot has helped that I joined a band where ALL the members are presently married with like-minded wives and they can all gather and converse as if it's an extended family where they can support or counsel each other. She comes to the shows, dances for us, get others out on the floor and watches me banter with groupies in some off-stage "PR" (which is only talking) but she's a really good sport about that stuff as she understands that it's part of being in a rock band where these things come with the territory. I think part of that makes me even more desireable to her while her being cool about everything makes her that much more desireable to me.
In the end, my wife also pushes me out the door, thinks I'm more tolerable to be around when I'm actively playing music and she too doesn't feel threatened by my music. She knows that at the end of the night (or tour), I'm going to end up in bed with her and nobody else. She also understands that allowing me to pursue my passion for music also benefits my passion for her. She understands that I'm one of those weirdos that esteems the spiritual expression of music above a**chasing...but only other impassioned musicians would understand that. It all depends on the mindset of the significant other because 90% of dealing with the perceived "threats" to a relationship that come along with ANY socially active lifestyle be it in a bar, church, community functions, company parties etc..is purely psychological.
That's not to say I haven't dealt with viciously jealous girlfriends before and usually this is what all female jealousy comes down to..is the gnawing fact in the back of their jaded thought functions that you *could* equivocally use music as an excuse to get a little on the side but just because you *can* doesn't necessarily mean you *will*. That's not MY problem, though. Most of the past jealous girlfriends I've had in the past were the ones that had the most deviant, twisted thoughts and ultimately acted on them before they would communicate their imagined animosities with me. Any female in the past that put her nutty thoughts before my productive needs quickly found herself packin.
In the end, crystal clear communication and "sticking to your guns" concerning a love of music is the key to nipping most of the problem in the bud (or a really sappy love song) lol. Alot has to do with the emotional stability of the significant other you are hooked up with and how they react to your gigging situations.