Make sure you add more value to that which you have while to strive harder to inculcate in that which you feel is absent in that which you value.
By doing so, you will naturally make that which you value invaluable.
Not liking or loving your partner anymore is an inevitable phase in a relationship/marriage. Hence, you must ensure you hang on in love, prayers, understanding and maturity because that phase will surely pass.
Some abandon their partners during this phase, funny enough, this phase still occur in the next relationship and instead of working hard to conquer this inevitability, they abandon again and move to next, next, next etc.