It is better, if you don not jump into a conclusion that your wife doesn't take things serious. If you have mentipned, one or two scenarios, it would be helpful to judge, what is the parameter of your seriousness. Because, I have also seen few couples, where the wife keep on complaining that my husband is not serious about anything. But by noticing I could understand that their brought up is different.
For example, When they were informed about the arrival of guest, she will call them in prior and ask about their arrival time, starts listing out the items to purchase, things about the menu, do laundry, keep telling about the kids, how to behave in front of them etc. She will look at her husband and will keep saying that why are you are not doing anything, tomorrow guests are coming, she will ask her husband to check the fuel in car, ask whether her husband's dress for next day is ready, will ask whether his alarm is set earlier etc.
I don't say that she is wrong. She is incapable of doing things at last minute. So, she wants everything to be ready.
Her husband, who is aware of fuel and does his things quietly or a kind of person, who is able to do things perfectly even at the last time, will stay quiet only. That doesn't mean, he is not taking things seriously.
And there are people, who trusts that everything around them will go positive, so will not get over excited or tensed for anything that did not go as planned. It is actually nice to have these kind of people, because they stay as positive energy around you.
You mentioned that she lies. I agree, it is bad. But there is a psychological research's result behind lying. If a punishment to any wrong is too high, then the people are tend to lie. So, see whether you have given a big punishments or criticized too much to her mistakes. So, in order to avoid such scenarios, she could have lied.
For example, If you have scolded her a lot for not having curd in your lunch and if you have skipped your meal. The next time, when she has forgotten to make curd, she may lie, that milk man did not come on that day, or the curd was not available in the store. If you practice forgiveness, her habit of lying will surely reduce.
Not serious about you, your family and son: To any women, her husband and son are more important than anything in the world. That too you have 5 years of married life. So, she could have got the attachment to the family. If not, she might have been feeling isolated from you all.
See that, she has given importance in your family. Discuss with her about anything that you do in your family. Involve her in family discussion. Ask her opinion. She might have hurt inside, so, keep speaking, don't just give up on one or two discussions.
I tell this everything from her point of view, because, understanding her will help you to find ways to resolve problem. See, whether you change or she changes, the result should a happy life and a happy family. So, understand her needs, act accordingly. The time she gets convinced and finds attachment to the family, she will also fulfill your expectations.