@Dinesh - It sounds like you just want your cake and eat it too! Leaving your first wife and children without the formalities of a divorce is the easy way out.
In my opinion, your first marriage is legal under HMA 1955. Remarrying again during the lifetime of an existing husband or wife is illegal and carries the offence of Bigamy, which is punishable under section 494 IPC - it carries a jail sentence of upto 7 years..
If you do remarry, your second marriage will be null and void, and if your new wife doesn't know you didn't divorce your first wife, then that brings in a charge of IPC 495 (concealment of a former wife) and a 10 year jail sentence.
You should seek a divorce under mutual consent - and pay your first wife maintenance for her and the children, and also give her a decent settlement - because if you don't, then you may just end up with a charge of ICP 498a and Domestic Violence Act instead. These will go on for years. If she becomes a 498a troll wife, then god help you.
I hope you havn't committed adultery either - that's a charge of IPC 497.
You'll be racking up loads of offences and they may just throw the book at you!
Do yourself a favour - go and see a reputable Advocate and do the right thing - get a divorce.
Good luck - your going to need it!