Q: I think my husband and I made a mistake several years ago concerning estate planning. He has passed away, and now I need to know what I can do to repair this mistake.

We set up an AB trust to avoid estate taxes. Now, with the increased estate tax exclusion, I'm afraid that I will need to put $2 million of our assets into this trust. The documents state that I'm the trustee and living beneficiary of this trust and my stepchildren are the final beneficiaries, whatever that means.

My stepchildren know about the trust and want to make sure I put the full exemption amount in the trust, even though that will be more than half of our estate. I'm afraid I won't have enough assets left on which to live if I abide by the trust. I don't understand the value of the trust and want to know if I can just ignore it.

I dislike the lawyer we used, so I don't want to meet with her and pay her any more money.

A: The most common reason for a couple to use an AB or other type of bypass trust is to lower or eliminate estate tax. It would be a shame to destroy this planning and subject your estate to more tax than necessary because you don't understand the trust document. Even if taxes aren't a concern, don't expose yourself to a potential lawsuit filed by your stepchildren.

If you don't want to meet with the lawyer who drafted your trust, I suggest you meet with another estate-planning lawyer. If you pay a professional to review your trust documents and provide an explanation of your options, it will be money well spent. You may also benefit by meeting with a fee-only financial adviser to determine how much money you will need to maintain your standard of living.

There are many benefits of an AB trust, and depending on the wording, you might have more flexibility than you imagine.

Here's a brief explanation of federal estate tax and the benefits of a bypass trust, which may be helpful.

Anyone can leave an amount at death, free of federal estate tax, equal to the amount of the personal exemption. Tax laws passed in 2001 increased the federal estate tax exemption from $675,000 to the current exemption of $2 million. The exemption will increase to $3.5 million in 2009, unlimited in 2010, and it is scheduled to drop to $1 million in 2011. Any amount over the exemption is subject to federal and state estate tax.

It's impossible to predict what Congress will do, but both presidential candidates have expressed a preference for either keeping the exemption at $3.5 million or increasing it to $5 million. A married couple has an unlimited marital exemption and can leave any amount tax-free to a spouse who is a U.S. citizen.

There are other benefits with a bypass trust. A married couple with a net worth greater than the estate tax exemption can reduce or eliminate estate taxes with such a trust.

Typically when the first spouse dies, an amount up to the personal estate tax exemption is placed in a trust. No estate tax is due on this amount, and the spouse is usually named as trustee and life beneficiary. Because the life beneficiary never legally owns property in the trust, this property isn't counted as part of the estate for tax purposes when he or she dies.

When the life beneficiary dies, the property in the trust goes to the final beneficiaries (your stepchildren) without being subject to estate tax. The trust document will state what rights the life beneficiary has to the trust property. You may have a right to all income generated by the property, such as a house, or the ability to use it. As trustee and life beneficiary, you can't have complete control to spend the trust principal, or the IRS will determine that you legally own the trust and will include the trust property in your estate for estate tax purposes. The trust principal may be spent for the health, education, support and maintenance of the living beneficiary, if the trust so states.

In all probability, once your trust documents are reviewed and explained, you will be glad you and your late husband took the initiative to add an AB trust to your estate plan.