Hi Friend,
I can certainly understand how you're feeling. I'm in a similar situation except much worse. You can read about my situation - jusy type in polygamist marriage. It's a very common problem where couples drift from each other, get caught up in the kids and get stuck in the same old pattern. It's normal for passions to fade. The question is - are there other qualities in the marriage that make it worth hanging on to. It's so important not to loose sight of what brought couples together in the first place.
Since you said he's a good husband and father, it could be he's just stuck in a lazy pattern. I think you should try marriage counciling like Shezbut said to see if the marriage is worth saving. If you do end up splitting then try to keep it as friendly as possible to ease the pain on both of you and the children.
I understand how you want more passion. But if there isn't any major problems like cheating, abuse of any kind etc. then you and your husband should try everything to save your marriage. You need to make him understand the seriousness of this and that he needs to do his part equally.
I hope feel better and find what you're searching for. Be thankfull you're not in my situation. Best of luck to you and your family.