Relationships require work! Regular check-ins are key and being proactive in order to keep the relationship on track is vital.

Be empathetic towards your partner. Be interested and try to understand why your partner is acting the way they are.
Make sure the positive experiences in your relationship outweigh the negative experiences by five to one. The key here is in noticing and acknowledging them.
Learn to calm yourself before you continue the discussion. Even if this means having some space for a few minutes to breath and then returning to the discussion. Learn what your partner needs during times of conflict.
When mistakes are made, make sure you both work together to repair the damage.
Be your partners primary support person.
Have a ‘team mentality'. When there are difficulties, talk about what ‘we' need to do about it.
Be prepared to listen and be influenced by what is important to your partner, just as your partner needs to be influenced by you.
Plan date nights or some form of regular time together doing something you both enjoy. Where possible add in some adventure or fun occasionally. If the adrenaline gets going so does the sexual desire!