I think to keep the fire going you both need to do things that ignite the fire in you both, like excitement etc. try to feel like an Teenager again and explore the possibilities . That is my take 
and the best way? is to treat your Wife always being Courted , Give flowers and always ask Her permission in everything so the Heat will remain forever. I do not want to offend anyone, but it seems to me that you cannot demand to support the honeymoon from only one side. It looks like using a partner. Official marriage and a family with children is always a search for compromises. But it so happens that one of the parties does not want to invest in the relationship. Why is that? Each situation is different. I chatted a lot on the Maturetenders. There are many people over 40 who have had unsuccessful marriages. I have never been able to find a unifying reason. I accepted the fact that sometimes we grow out of relationships. Then you should put up with it and move on.