I've read all the (different sounding) replies. What you have to understand is, as "bandcoach" basically hinted at "love is about completing each other, not about making sacrifices".
And you guys already started out with making sacrifices; you have to deal with her 2 kids, you have to deal with the distance, you have to deal with it being basically a weekend-relationship.
This is/can be a very bad basis for a long lasting love, because to be honest, you guys don't know what it's like to be together 24/7 AND you are a weekend daddy to someone else's kids; it doesn't matter NOW, but it will matter at some point, be it due to arguments or due to the fact, that the kids will grow up and start to question your authority ("you are not their father/you are not my father").
"Love is color-blind", they say and sometimes love is about seeing everything in either black or white. So either everything is bad, or everything is good. That's never the case.
You know, it's funny, but the more attention you give a woman, the less the values your time, the more you value your time, the less attention you get.
Basically, if you spend too much time living a life "for her", the more she wants you to go away. The more your work/study/care about your needs, the more she will call you an egoist.
You can never win.
Also, keep in mind that pursuing a career in music means spending MORE AND MORE time doing your job. 14-16 hour days are sometimes the norm, I don't work during the holidays.........but sometimes I have to. Can it work? Sure. My aunt was an accountant before she married my uncle and he's a steward on these cargo vessels and for the last 20 years or so has been away from home for months. They make it work somehow and have no problems in their marriage. Then again, there are people who have a weekend-relationship and once they move together, they discover a completely different person, all of a sudden.
I was with this girl who I had to fly over weekends to. Sure, I can afford it, but that's not the point. I did it, because she grew up in her city, always lived there, all her friends and family lives there. Didn't want to be the egoistic type, who forces her to leave it all behind, just to be with me. She simply didn't want to leave her city and live with me here. Guess what? After I broke up with her, because I didn't feel like she was ready to make the sacrifices I was ready to make and she got together with some other dude, all of a sudden, living with her fam and friends wasn't that important anymore.
See, because I was ready to change MY life, she wasn't to. Because someone else wasn't ready to change his life, she now is ready to do it. That's pure egoism. You want something so much, that you are ready to forget WHAT ELSE YOU WANT or WHAT'S REALLY IMPORTANT TO YOU.
Thing is - it's HARD to find someone who COMPLETES you, most of the time, you will only find someone who makes you feel good, as long as you are making sacrifices left and right to make it work. Which is not a good basis for a happy life.
Also thing about what bandcoach said; he and his wife have four kids.
You would be responsible for TWO already and I guess you want to have kids with her as well; it will be hard to BOTH, spend this amount of time pursuing your dreams AND make enough money to live a good life yourself, LET ALONE feed you, your wife, her two kids AND the ones that might follow later. Think about this logically.
And no matter what - this is YOUR life.
This is my realistic outlook on things and I don't know of an easy algorithm, how to decide these things, so I won't tell you what to do; just think about what you would tell a friend, if he told you about being in a similar situation and not being sure, which path to take.