I'm an artist married to another artist! We both went to the college with the same major, worked in the same field (even the same company once) and we both create art. We've been together 13 years and married for almost 8 now. While I definitely understand the trepidation that a lot of folks feel about dating other artists, especially in the competition side of things, that hasn't been my experience.
I think it comes down to the frame of mind. In my relationship we create seperately, but more importantly, we create together! Finding a project that we can work on as a team has only made us stronger in our skills and relationship too. The comic I work on literally wouldn't exist if we allowed petty BS to get in the way. You have to put aside your own ego. Get rid of the "I" and start talking in the "we" context.
When you're in a relationship, you've formed a team. My husband gets a lot of gigs that I've applied for, not because of my lack of skill, but because he just knows more people. Meanwhile, I've gotten gigs that he's applied for because I have skills that he hasn't focused on. It's not personal. A win for one is a win for you both. When my hubby gets the job: OMG YES! MONEY! CONNECTIONS! Let's mine this baby for all it's worth! When I get the job? Spoiler! It's the exact same thing.
Being in a relationship with another creative isn't about one upping eachother, it's about helping one another grow and thrive. Working on our comic we've come closer and honed our skills further than I ever imagined. And not all artists are created equal. Where I lack in some skills my husband excells. Where I excell he struggles. This allows us to learn from one another and become better for it.
Ultimately when you're working in art you also have to come to a conclusion: What's more important? Your relationship or your art? Now, I really love the work I do on my comic. It's basically my life and career, and I love every minute of it. BUT if came between giving up the comic we make or giving up our relationship? The comic is toast every time. A creative couple can't work unless both parties know where the breaking point is, and which comes first. For us it's eachother - we've pointedly sat down and decided together that we will not risk destroying our marriage for the sake of a comic. It's not worth it.
I know I'm a lot older than the majority creator base here, so take it from this ~old lady~ and remember that you're a team. What's good for one of you, is good for BOTH of you.