I would like to add my 2 cents on what makes a relationship healthy and also recommend a great book if you want to dig deeper. Without further ado, here it is: 

1) Accept, don’t expect.

Unconditional acceptance is something we want, but rarely ever give. People never do anything that is out of character. They may do things that go against your expectations, but what people do reveals exactly who they are. Never force your expectations on your other half, other than the expectation that they will be exactly who they are. Book to read: “Getting the love you want” (http://amzn.com/0805087001)

2) 50 shades of…

Even the healthiest relationships have flaws. Being too black and white about the quality and health of a relationship spells trouble.

3) Focus on the good things

Instead of constantly looking for signs of what’s not working in your relationship, what you need to do is look for signs of what is, and then use this as a solid foundation to build upon.

4) Always show appreciation, even for the small things

Whether it’s
something big or small, always show your appreciation for your partner whenever
they do something for you. People often fail to show their appreciation,
especially if they have been together for a long time. A lack of gratitude will
make the other person question how much they are valued in the
relationship.