Very few people are really aware of the inner call. Ones who think they are, get mixed up between listening to their mind and listening to their hearts. There is a very thin line between the two, and it needs great skill in assessing whether the voice is the mind's or the hearts.
I've suffered from this confusion which led me to doing things which I would never have done. But if you are so sure that its your hearts calling (and I'm sure it is), i would suggest to do it NOW. there are various reasons why we DEFER listening to our hearts.
Some people are scared of the outcome, some people are skeptical of the results, some are not able to shed of the pressure of their family, some listen too much to the intellect. But in all cases, even if at times listening to your hearts true calling may seem ridiculous initially, that is what we should do. In fact Swami Vivekananda (a great saint of recent times in India) said exactly this. He said that the intellect is limited by our understanding, experiences and various other factors. But there are no limitations to the domain and the capabilities of the heart. That is why whenever one is stuck between listening to the intellect and listening to the heart, go for the latter, no matter how ridiculous it seems.
Another thing he said is that, in ancient India, thousands of years ago, people had discovered and acquired knowledge of the subtlest portion of matter, about planets, about the universe, about earth, about life. But in those days there were no hi-tech gadgets or equipment. so it was possible by the continuous purification and synchronization with the heart. So I would suggest you to do it now.
The least is you will be happy...

Dear Sourabh, I don't want to be a wet blanket but it would be best to make sure that you are ready for your dream before embarking on it. The Job you have at the moment pays you a regular salary and in the dream job you will be paying your own salary. Can you afford it? I'm all for you living your dream but if you save a years worth of living expenses than you will be able to survive a year without having to worry where your rent, food and other expenses will come from and at the same time make it more enjoyable in your dream job which will make it easier to be positive and attract clients or whatever it is you need. Think and look before you leap.

On the positive side do your LOA meditations and create that which you want. Imagine yourself living your dream life already with very positive aspects and you will attract it.

About your present job. Below are some pointers on how to learn to love the work you are doing at present so to make your remaining time there as pleasant as possible. Every morning on awakening or whenever you can remind yourself of these.

1. Does this job pay for your groceries? If it does it is the first reason to love this job for it sustains your and your families life. You won't die of hunger.

2. Does this job pay your rent? If it does great for that is another reason you should love this work for it provides a roof over your and your families head. You will not get wet when it rains or too cold when it's freezing outside.

3. Does this job pay for the clothes you and your family wear. If it does excellent for you can dress warm in winter and cool in summer to protect your body from the elements.

Those are just some of the reasons to thank God that you found this work and to be grateful, appreciative and love the work you do for the short amount of time you will still be there. It will make your time there easier and happier to bear. When you are happier it is much easier to attract the good things in life and the sooner you can live your dream.

If this change that you DESIRE is so burning and encompassing. It will come. BELIEVE that!

Get out into the sunlight — out where everything is — with a vibration that is so dominant that those who annoy you; those who don't agree with you; those who make your life feel uncomfortable don't come into your experience, because your vibration — through your practice — has become so clear, so pure, so clean, so in keeping with what you want, that the world that revolves around you just feels like that. That's what you planned.

--- Abraham

The resistance that is put forth by your wife is a good thing. It adds more wood to the fire burning within you. To see the road you want to follow. The timing of the change will be clear to you when you work through the resistance you feel and the feeling is right/in the Iortex. Be aware of your feelings/heart.
peace

consider the positive and negative aspect from your job. do the same with your business. try to solve the negative aspect. once you will be ready to make the move you will know it. if their is no more negative aspect you will not have anny doubt. experience and enjoy.

Have you considered that you may be resisting the resistance of your spouse as far as wanting to quit your current job right now? I'm not saying it's definitely the case by any means. It could also just be some impatience on your part too, especially knowing that your current job is not in a field that excites you. Do you possibly have a fear that if you stay in your current job for another couple of months that you will get to the point that it will be draining your energy? You also need to consider how important it is to you to honor your spouse's wish to wait at least a couple more months. These are just a few questions/things to consider.

I'd do some journaling asking for guidance. However you might believe in that guidance; angels, spirit guides, higher self. Get yourself in a quiet place and a calm state of mind. Then just write, Dear Higher Self -- and ask your question(s). Then write Dear Sourabh, and just let yourself write whatever comes to mind. Do this several times and see if what your answers are. You can write your answers with your non-dominant hand. I find this especially helpful because it gets me concentrating on writing well enough to actually read what I'm writing that I get out of being logical or rational (hence it's actually me answering) to get down to better answers.

Hope this helps a bit :)