Apurva:

If you are able to see a doctor there is an injection called DE-Provera that can be given to your wife which will give her pregnancy protection for three months after which time it has to given again to last another three months.

I am not a doctor but I have worked in a doctors office.

Condoms are great as they are not chemical. The "depo" drug once had a theory that linked it to cancer. I don't like any such risk.

I know that anti-depressives tend to take away sex drive. They take away the urge and the ability to ejaculate. You won't get depressed either, they are anti-depressives. To be real, you need to see the doctor.

Your wife needs a good rest for a few years. That is not a long time. If you are Hindu or Buddhist, you would understand the principle to hold on and be patient with no desire, and there will be no destination but many diversities. May happiness be yours, and I think you will have another child in about 4 years.