Seattly relo had a very good suggestion, but one should also caution that insurance companies are part of the financial mess — including the derivatives that are at the center of the problem. One never knows for sure if the insurance company will be able to pay the claim.
I would also strongly recommend you talk to an attorney. Quite frankly (this goes to anyone else thinking about remarriage when there are existing children), you should have talked to an attorney BEFORE getting married.
That being said, talk to an attorney, especially one who specializes in estates and trusts. There are options with trusts where if you pass away, your “half” of the property goes into another trust that goes to your son. You can make all kinds of stipulations, like the wife gets to live there until she passes away or sells, and then the property goes to your son, etc. Lots of options, and you should explore every one **with an attorney.**