Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.
Genesis 2:24

The definition of "cleave" is an odd one. There are two meanings: "Split or sever something" and it also means to "Stick fast to". Yet there's no doubt of the meaning when it's used in Genesis 2:24. It's God's intention that husband and wife stick fast together. Marriage is a blessing that is meant to sustain and nourish the partners. Define cleave in the positive and keep it together.