As the first part of this article discussed, spouses who enter a second marriage with grown children must work through a host of difficult issues to build a harmonious relationship among family and step-family members. As you can imagine, parents with younger children who choose to remarry shouldn't expect a walk in the park, either. Although the particular difficulties parents of younger children face differ, it's still crucial for both spouses to reach common ground on how they will deal with their newly melded families.

Families with young children
Financial planning for couples with young children from previous marriages can be extremely complicated. Unlike their counterparts with adult children, parents with young kids face the considerable financial obligation of raising them. In addition, while older couples can generally disentangle themselves from their former spouses, many divorced parents of younger children have shared custody arrangements, child support and maintenance payments, and the logistical challenges of trying to accommodate the needs of both the children and each parent. These difficult considerations can put a huge amount of strain on a new marriage. If only one spouse has children from a previous marriage, the other spouse may not understand the effort it takes to find viable solutions to the issues involved. If both spouses have their own children, on the other hand, it only increases the amount of strain, constantly pulling each spouse away from the other to deal with the dynamics of each one's previous relationship.

Couples in these situations have to come into relationships with their eyes open. Many parents place their responsibility for their children above their own happiness, which can quickly weed out dating partners who aren't prepared for the challenges of being a stepparent. A commitment to understanding and overcoming these challenges can provide a strong foundation upon which couples can build their new family.

From a financial standpoint, the difficulties involved with spouses who bring children into their marriage require creative thinking and open-minded solutions. For instance, if one or both spouses must pay substantial amounts of alimony or child support payments to their former spouse, the resulting diversion of cash away from family finances can force the new couple to postpone plans that might otherwise have been achievable fairly quickly. While it's easy to resent your spouse's ex for putting a crimp in your dreams, you should realize that the situation has few differences in practice from what you would face if you married someone with substantial credit card or other personal debt. It's hard to come up with one-size-fits-all solutions to these problems; more frequently, couples must customize their solutions to their own personalities and values.

Dealing with half-siblings
One situation that often arises in second marriages among younger spouses with children is that the spouses decide to have children of their own. The resulting family structure, with stepchildren potentially on both sides of the family with half-siblings in the middle, can wreak havoc on conventional financial and estate planning.

In planning your finances, you first need to evaluate your particular family situation. Are you the only parent in your children's life, or will shared custody with an ex-spouse constantly remind your children that some of them are different from the others? It's often easiest if children can simply think of themselves as all being part of the same family, but the realities of modern life sometimes make that impossible. Do some of the children have greater financial resources than the others, as a result of child support payments from an ex or family legacies or inheritances that only provide for blood relatives? If so, you probably want to do whatever you can to avoid any perception of favoritism among the children in your household.

Over the longer term, the decisions you make while your children are still young will have a big influence over the way you handle financial issues that concern them once they're adults. If your children and your spouse's children successfully grew into a single cohesive family unit, then there's probably little reason to make arbitrary distinctions among them in preparing a financial and estate plan. On the other hand, if the children have grown in different directions and have divided into apparent opposing factions, you may have a real problem on your hands. As always, the best way to solve such problems is through communication, but you shouldn't feel like a bad parent if you find it impossible to get everyone to talk with each other. In those unfortunate cases, you and your spouse can work together to figure out a plan of action that will at least meet your mutual needs, and hopefully some of the needs of your children as well.

Finally, from a legal standpoint, it's important to understand how your state's inheritance laws treat stepchildren. In the absence of contrary provisions in a will, a child is usually entitled to inherit from natural parents, but not from stepparents. Some states even still retain antiquated distinctions between half-siblings in determining inheritances. By clearly stating your wishes in your estate-planning documents, you can avoid any disputes arising after your death that could spell the end of your children's relationships with each other.

Second marriages among parents present some of the largest challenges that one can face in financial and estate planning. By remaining diligent and acknowledging the situation, however, spouses can overcome these obstacles and create the family that they always hoped to have.

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As the son of a divorced and remarried father, Fool contributor Dan Caplinger has experienced the fun and folly of stepparent finances firsthand. 'Til death do you part with the Fool's disclosure policy.