Should a married couple separately attend two different churches?

Although some couples decide to keep attending their own churches to retain their preferred denominations, there is a risk attached to this arrangement. Practically speaking, it’s unlikely for a family to plug into two different churches and grow in fellowship with two different groups of people; most likely, only one or neither parent will become highly involved in church life.
With children in the home,
a multi-church family situation becomes more complex. Parents may communicate opposing versions of faith to their children or give their children the choice of whether or not to participate in a faith practice. In our secular culture, giving children authority to choose is hailed as great parenting; many secular celebrities promote that exposing children to all beliefs and perspectives is sure to produce analytical thinkers who know what they believe.
However, the opposite has been proven true. Millennials as a whole show more spiritual interest, but have less Bible knowledge, less faith in denominations, and less belief in absolute truth and the Bible than any previous generation. Pluralism is replacing Christianity in America, even among kids who were brought up in Christian homes, and it’s leading them into agnosticism, cults, and the Eastern religions.
God makes His position about Christian parenting clear in Scripture: parents are responsible to lead their children toward the Lord. 

• Train and instruct children in the Lord (Ephesians 6:4)
• Continually impress on your children a love for God and others (Deuteronomy 6:4)
• Raise children to serve the Lord (1 Samuel 1:27-28)
• Give children a God-worldview (Deuteronomy 6)
• Children trained to know the Lord will have a natural desire to follow Him (Proverbs 22:7)
• Hindering children from coming to the Lord is a heinous act (Matthew 18:1-6)

Ultimately, children can and will choose for themselves whether or not to believe in God. They will also choose their own church communities when they are grown. And like everything else in life, they will base their adult decisions on what they observed and practiced growing up. If they grew up in an environment where every belief was hailed as equal, they will deduce (minus God’s intervention), that they can decide truth for themselves.
How and where you worship reflects your personality and expression, as well as God’s authority in your life. God intends your church to become your family, a place where you serve, grow, give, and relate to others who share the same faith and values. Your local church isn’t another club or community service opportunity where you can decide when and if you’ll participate. It’s a living, breathing organism called Jesus’ body, and God has called you and your loved ones to become physical members of that body.
So if you’re dating someone from another religious background, take the opportunity to investigate both traditions. (Do you even know what your theological differences are? Are you both Christ-followers?) Analyze, pray, and decide: will one of you switch denominations, or will you choose a new denomination together?
The choice is yours. Just base your decision on God’s word and the prompting of the Holy Spirit. Anything else is either foolish or reckless.