1 what can be the next course of action from my end.
Dont give up the DV case in between. You may file an application for residential rights in his parents house claiming it to be your matrimonial house and you can barge into the house, if need be, you can take the help of local police to protect you from possible assaults by your in-laws side.
2. legsllyCan I use my husband name on my child birth certificate, which I'm about to deliver in few days, since my marriage is bigamous now.
The marriage only is bigamus but your children are not illegitimate. They are entitled to be named after their biological father. You have to register the child's biological father's name only.
3. If I take my case back will it amount to defamation case against me although I have all proofs backing my statements and claims.
No defamation case can be filed on this, but why do you want to withdraw, let the case go on. Dont lose your rights by withdrawing the case.
It is just that husband has ran away to live a nice life and both the kids are my responsibility and somewhere I'm feeling that. M losing my time and money on case where I don't see anything happening
It does not means that you have lost everything, you fight the case and get an exparte decree which may help you anytime in future.