How a New Relationship Can Affect a Divorce or Custody Case

Under Missouri law, a remarriage automatically ends statutory maintenance. Moving in with a new partner doesn’t. That’s where most post-divorce disputes about new relationships actually begin, and it surprises people on both sides of the case.

Remarriage Ends Maintenance; Living Together Only Opens the Door

Section 452.370.3 of RSMo is direct. Unless the parties agree otherwise in writing, or the judgment explicitly states otherwise, the obligation to pay future statutory support terminates upon the death of either party, or upon remarriage by the party receiving support.

Cohabitation works differently. Missouri does not recognize common law marriage, so a live-in partner does not automatically end maintenance. What the statute requires is this: when deciding whether circumstances have changed significantly and continuously, the court must take into account all financial resources of both parties, including how much each party’s reasonable expenses should or should not be shared with a spouse or other person they cohabit with. The paying spouse still needs to file a petition and prove the new household economy. Nothing happens automatically.

A New Partner Affects Custody Only When It Affects the Child

Missouri courts do not award custody based on who moves on first. The question in Section 452.375 is about the child’s best interests, and a new relationship becomes relevant when it relates to one of the statutory factors. What draws judicial attention:

• A partner with a history of violence, substance abuse, or criminal behavior who is around children
• A parent whose new relationship interferes with the other parent’s time with the child, as the willingness to encourage frequent and meaningful contact is an important factor that the court must consider.
• Adult conflict playing out in front of children
• Household changes that make the current parenting plan no longer suitable.

Dating during a case is not misconduct. Giving a new partner the role in parenting decisions, school communications, or exchanges, is where custody cases arise.

Money Spent on a New Relationship Is a Property Issue

Missouri is a no-fault state when it comes to granting divorces. However, it is not a no-fault system when it comes to dividing up the assets of a marriage. Section 452.330 outlines the conduct of both parties during the marriage as one of the five factors in arriving at a just division. Missouri courts have traditionally interpreted this section broadly, rather than limiting it to financial matters.

The sharper argument is usually dissipation. Marital funds spent on a new partner, whether trips, rent, gifts, or a vehicle, can be traced and charged back against the spending spouse’s share before the division is made. Pull the statements early. Once the division has been entered, it is final, so there is no way to correct it afterward.

Moving In With a New Partner Can Trigger the Relocation Statute

If moving in with a new partner results in the child’s primary residence changing for 90 days or more, then Section 452.377 will apply. Written notice must be sent to every party with custody or visitation rights via certified mail with return receipt requested at least 60 days before the move. The notice should include the new address, phone number, date of the move, specific reasons, and proposed revised schedule.

The other parent then has 30 days to object in writing. Skipping the notice is costly. A violation can be treated as a change of circumstances that allows the court to modify the existing custody judgment, and the court can order the relocated parent to pay the other party’s costs and attorney fees.

Talk to a Columbia Attorney Before the New Chapter Complicates the Old One

A new relationship rarely decides a Missouri case on its own. It changes household finances, children’s routines, and sometimes addresses, and each of these has a statute attached to it. When you face a difficult family law issue, contact Columbia Family Law Group LLC right away. Our more than 35 years in the Missouri legal system has earned the trust of families in the Columbia area, and we can tell you what your new relationship will actually change in your case and what it will not.