Well man, handling a wife who is too negative about the practice of poker can be difficult, but never impossible.
I believe the most important thing here is: What really do you expect from playing poker? Is it a hobbie for you or do you have any intents of playing it professionally?
To start from here, if you just want to play for a hobbie, you should not be really fighting with your wife, just play when you have time to do so and she is elsewhere.
But if you really want to improve your game and make it your main money income, than not all hope is lost. I have decided to dive into the pokerworld recently and my wife didnt take it very well too, in the beggining she was very irritated when I was playing rather than staying with her, and she was constantly doubting about I been capable of making money with Poker. By went by and we kept fighting for the same reason, until one day i decided I would have to take a stand if I really wanted to make Poker a Profession.
That's when I took her out and we discussed it over dinner. I told her that despite what she thinks not only is possible to beat Poker as there are thousends of people making money out of it and that this is what I really wanted to do for a life. Then I explained for her that nothing comes down from heaven and in order for me to be able to make money out of it I would have to be studying the game in a daily basis. After a long talk she was convinced that Poker was not just a hobbie for me and that it is serious business.
When I had her convinced (that I was going to take a shot at it, not that I would really make any money out of it cause she still kept skeptical about it) I made a week schedule with several hours dedicated for playing and studying.
Today she takes it like if I was studying for any other profession and even supports me to get my game better, even though she still gets a little upset when I'm playing out of the scheduled times.
Anyway try to be clear about what you really expect from Poker and put it in a balance against what you are willing to go through with your wife to get it done.
Good luck man.