“Commit. Listen “actively” to your partner. Ask questions. Give answers. Appreciate. Stay attractive. Keep growing intellectually. Include her. Give him privacy. Be honest and trustworthy. Tell your mate what you need. Accept his/her shortcomings. Mind your manners. Exercise your sense of humor. Respect him. Respect her. Compromise. Argue constructively. Never threaten to depart. Forget the past. Say “no” to adultery. Don’t assume the relationship will last forever; build it one day at a time. 

And never give up.”

Fisher, H., Why We Love: The Nature and Chemistry of Romantic Love