To achieve success at anything, focus is an absolute must. If you're an artist or an entrepreneur with a great idea, chances are you tend to discover and/or attract other great ideas. This is a double-edged sword.
On one hand, you know you will never run out of ideas. This gives you the unshakeable belief that you will eventually succeed with enough effort. Never do you fear an idea that fails, because there is always another path to be taken.
On the other hand, every great project has points when it seems hopeless. Having an unlimited reserve of good ideas (and even great ideas) makes it very easy to justify cheating on your project. You know the one you swore on your life would take you to the top?
Did you mean it when you thought it? Is it really over? Is there no salvaging it? Yeah, your project is not only your brainchild, it's also your husband/wife!
First you have to court it to learn if it's right for you. Fall in love with it for sure, but also learn everything you can about it. Don't get seduced. Second, armed with passion and understanding set the commitment in stone to finish what you started!
Eventually, you will be able to see the boundaries. Then you can have intimate friends on the side. Never mix up the natures of your respective relationships (in either case). Until you see the boundaries, you need to keep friends (and intake other projects) that themselves understand, respect, and enforce those boundaries which you cannot see.
In relationships, as with projects, success does not come from hopping from one to another at the first sign of trouble. It comes from putting all your eggs in a basket you understand and love, then guarding the basket with your life. No matter the problems.