To remarry after the death of a spouse can be traumatic for some family members. If the widow you want to marry is a well-adjusted woman who has come to terms with all of the issues involved, you're in good shape.
Proceed with caution if you want to marry a widow. Issues will, of course, depend on the circumstances surrounding the lady. Ages of any children involved, the widow's age and financial status and attitudes of other family members can all be factors in how to proceed.
Consider the children, if they are still underage. Make sure you take time to get to know them and establish trust with them. Do all you can to have a meaningful relationship with them, without trying to take their dad's place. Even if the children are adults, let them know that you want to be friends with them. How well you handle the situation concerning the widow's children will play a big part in the success of the marriage.
Settle on which home you will live in after you marry a widow. You must decide this together before you marry. Whether it's your home, hers or another you purchase together, be sure that you are both on the same page when it comes to living arrangements.
Think about whether or not you need a prenuptial agreement before you marry a widow. Opinions on this differ greatly, but largely depend on the financial status of those involved. If you marry a wealthy widow, her adult children may demand a prenuptial agreement in order for them to feel confident that their interests will be protected upon the death of their mother.
Be prepared for negative reactions and attitudes of the widow's parents-in-law, if applicable. If there has been a close relationship there, they may resent your coming on the scene. Especially if young children are involved, try to be patient and understanding of resentments while everyone adjusts to the new marriage.