Cue scene. Two people, attracted to the other, enter into a form of friendship that seems to extend beyond the capacity of a friendship. Slowly, as time goes by, those two people begin to build a new sort of relationship; one that is the curation of the experiences they've shared together as a couple. It's an awesome thing to watch others go through, and to have the opportunity to experience yourself.
However, all romantic relationships, particularly those started when both people are young, can be difficult to keep growing. The key to keeping them healthy is a layer of trust and honesty between those two most intimately involved in the relationship: each person and God.
Being able to have a strong layer of trust and reliance on God is an amazing thing to have. All relationships are going to have tough times to work out and won't always be flowing smoothly, but having that relationship with God to fall back is incredibly comforting in times of stress and uncertainty.
Knowing my relationship with Him is forever with me has dramatically changed thew way I view relationships. When I look at the relationship I have now, I see three parts: me, my lovely girlfriend and God. Whenever either she or I have felt the relationship wasn't clicking as well as it could be, it's usually because we have payed too much attention to the Two Part relationship, not the one where God is ever present, constantly speaking to us. When we refocus to that, our relationship deepens and grows like crazy.
Relationships are tough, but with God nothing ever seems insurmountable. Time, practice and patience are required. Coffee+devotional dates are necessary. And you must be willing to listen when He speaks to you.