3. Lack of shared rituals.
Rituals or, if you will, traditions that you keep in your family are very important. All those things that make you stay together and share something with each other unite the couple. Create your own rituals like regular walks, reading or going to the swimming pool.
4. Ignoring opposite-sex friendships
Beware of this kind of relationships. Most of us have them. But if friends become too close, it may be the main cause why your couple is collapsing. Do not believe in innocent male-female friendships. This is how all love affairs start.