But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law.
There are many different resources available to you to tell you how to be nice to your wife. Books, movies, television, the internet. But all you really need to know is...do not ever take her for granted. Always show your appreciation for having her in your life and tell her frequently that you love her.
Keep in mind that it is the little things that count the most. A foot rub for tired feet, a neck rub after a particularly stressful day, supper on the table if you are the first one home, a smile greeting her when you see her, helping with the laundry or dishes. You get the idea.
If things between you have cooled down considerably over the most recent past, try to figure out the reason for it. Whether or not you have done something wrong, it may be up to you to fix it. If you don't, things will only get worse.
Maybe you have been spending too much time playing video games and not spending enough quality time with her. Put the video game away and ask her if there is anything she would like to do for the evening. Then, whether you want to do it or not, go do it. Putting her first for a change will make her feel important in your life and not like she is playing second fiddle to your video game habit.
A woman wants the most important man in her life to be attentive, helpful, cuddly, snuggly, loving, and respectful. seems like a lot to try to keep tabs on, but it really isn't. Like I said it is the little things that count. For example, if the two of you are watching TV together, sit and cuddle on the couch. Cover up with a blanket.
If she should happen to not feel well, fix her some soup and buy her a magazine she would like to read while she is recuperating.
Try to tell the difference between when she is just venting about a situation and when she really does want you to fix the problem she is having. If you can't tell, then ask her, she will let you know in no uncertain terms which one it is. If you can fix it, then do. If you can't then don't even try but tell her you don't know how, do not just ignore the situation. And don't be embarrassed, she already knows you are not perfect.
Obviously, these suggestions are not all the things you could learn regarding how to be nice to your wife but they will point you in the right direction and maybe help you see things in a different light.