Love is patient, love is kind. It does not envy, it does not boast, it is not proud. It is not rude, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. Love does not delight in evil but rejoices with the truth. It always protects, always trusts, always hopes, always perseveres. Love never fails. . .And now these three remain: faith, hope and love. But the greatest of these is love. -- from 1 Corinthians 13:4-13

I am thinking of an everlasting love, not just a few months in my answer. I believe the following things to be important: trust, respect for one another & agreed beliefs about your cultures, marriage & children & whether both will continue to work whilst the children are small.

trust

Honesty and loyalty above all are the most important.