My wife left my house along with 7 months daughter

Do as I tell.  Go break your mother in laws head.  She is the root cause of all the problem.  Dont break wife head.  You will need wife but not mother in law.  If possible break father in law head also.  Go.  Take a oar and do it.

Bhai mere... tumko shaadi nahi karna tha, Isse accha yahi tha ki tum paise kamate, mauj karte, apne ma baap ki acchi dekhbaal karte.   Yeh shaadi ka jhanjhat tumko parodta nahi.

Now you want divorce and also chlid but not wife, you are fed up with wife.  You want child?  That is another headache man.  Dont take kid back.  [you ask court, file G&W, roam to court for 5-6 years, pay alimony to kid, wife also under 125 crpc].  If you take back kid, who will look after kid, you?  You cant, you will ask your mom to look after it, your mom looked after you, now you want her to look after your kid also, what karma of your mom that she look after your kid too?  Dont you think you should not trouble your parents in this old age?  Why did you marry in the first place?  Did you marry your wife thinking that your parents will look after her and also your kid?  What a loser you are.

Getting divorce is not easy.  And the above grounds are laughable.  You wont get divorce based on the above reasons.  

Your wife dont have any work.  She does not listen to you,  She listens only to her mom even now, shows that she has not still understood the fact that she is already married.  She thinks that her mom only can give best advice, she is not in a position to understand that you are her most important person.

First tell your wifes parents not to interfere in your family life.  Talk to your wife and make her understand your problems and not to act childish.  She understand and stops all her foolish ways, good for you all.  Warna there is court always, it will accept any bl**dy application by anybody.  Then ghoda he maidaan he.

You got married to such a women is your fate, not your mistake !

The root cause of the problem is your Mother in law and she will not change let me tell you as she has vested interest in extracting money from you through her daughter. (soch galath hai!)

Your wife also does not realize whats good for her, no matter how much you talk to her and make her understand it will not help............ek kahawat hai - Ghode ko paani peene ke liye aap talab leke jaa sakte ho, lekin paani to usi ko peena hota hai !

Your wife is using your son as a tool to blackmail you and she knows very well that your son is your weakness. Be practical - your wife has taken away your son and she is taking decisions for your son (whether good/bad) all by herself, our laws are such that you will not get custody of child till he attains 5yrs age , you do whatever you want but that's the reality (considering the facts of your case)

I suggest leave her on her own for 3months, dont show any interest in her and son (though you care but for sometime). If your wife learns a lesson she will return or else she's gone forever. 

Taking her back later is a headache for lifetime, gather solid evidences on adultery and file for divorce,also fraud -420 for forged certificates.......

@Author - You have mentioned the second marriage is a Love marriage. What qualities did you look at her or you just saw her beauty and got married.

After your 1st divorce, you thought if you have a wife that is enough who can take care of you and your family.

She was looking at your money, Your 100 yards house, not you. Money is the root of all evils. 

You should have done thorough background check and make sure she is the right person for you. Ok Past is past.

Be Patient and Silent. As mentioned by others even if you go to Court you will not get Custody of the child.

Read the artice by Natarajan Iyer...

https://www.lawyersclubindia.com/forum/2-nude-photos-and-answer-to-divorce-by-mathematics-112864.asp

https://www.lawyersclubindia.com/forum/Man-choice-or-compulsion-112821.asp

https://www.lawyersclubindia.com/forum/Hit-out-and-then-get-out-112777.asp#.VHNUSPldWzI

Even if you go to Court, she might file false cases, alimony and maintenance for child. If she threatens you, don't fear and have the Courage to face the hurdles.

Also Helping Hand has given his prompt advice.