Mark Manson wrote about 6 healthy habits that people feel are toxic, but that can actually help your relationship be healthy.

http://markmanson.net/6-healthy-habits

For me number 1 "letting some conflicts go unresolved" has had the best impact on my relationship. I did think at first that every little thing had to be fixed and sorted. But over time I came to realise that if I was going to do number 6 "accept my partner's flaws", then I would need to just let some things go.

What I do now, is first have a conversation with myself and then I write a journal entry on the thing thats bugging me and then I decide how important it is to resolve what ever the issue may be.