Need some advice with my 9 year old son...

First of all, a tiny bit of back story. His mom and I (his dad) are not together. We share custody and there's no hard feelings between us. My son is pretty smart. He gets A's and B's. When he first started school, he had some problems comprehending and learning. At his mom's house, he's surrounded by girls. His mom is lesbian, with a partner. He's got an older 13 year old sister (also mine) and a younger 3 year old sister. When he started struggling in school, I feel like he wasn't helped much when he was at his mom's house. His mom's partner isn't a great "step-mom", in my opinion, and it took me sitting down and helping him with his homework for everything to really click. Now, like I said, he gets A's and B's.Keep in mind that this is all coming from me, his father. It seems like he hasn't developed any interest or need to learn anything extracurricular. Like drawing, writing, music, building, or anything. I'm not sure if it's because me and his mom aren't able to stimulate anything like that. I do have a feeling that he doesn't get enough attention at his mom's house (due to her relationship and the youngest of the kids taking up a lot of attention). He DOES get attention at my house (I'm still single, and live alone), and I try to get him interested in those extracurricular things.When he DOES open up to me about stuff, it's usually to kind of complain about his mom or her partner. In my opinion, that's kind of normal, and I do not bad mouth his mom or reinforce the notion that she's in the wrong. She IS a good mom, but I DO think she's a bit overwhelmed. Of course, I don't tell him this.I guess I have 2 questions: do I need to worry that a 9 year old hasn't developed any interest in extracurricular activities? Also, how do I handle that he's opening up about his mom? I understand that it's normal for kids to complain to each parent about the other one. But, being a single dad, not living at that house, I'm not too sure on how to handle it.Any advice is greatly appreciated. Of course, there's a huge story behind all this, but I'm summarizing tremendously so as not to bore you all to death... If there's any questions, I'll answer them. via /r/Parenting http://ift.tt/2oERC9w