In all of my relationships, the one key factor that lead to their ending was poor communication or a lack of desire to communicate on a deep level.

After being a married man for 10 years now I can honestly say that the main reason for problems in my marriage are when my wife and I don't communicate effectively, and we generally fix our problems when we start to talk properly again. Just recently, we agreed on a very significant purchase that set us back financially for some time. My wife only told me afterwards that she didn't really want to go through with the purchase but agreed to because she thought it was really important to me. If I had an inkling for even one second that she wasn't comfortable I wouldn't have gone through with it.... this lead to some fairly big arguments however now that we are both on the same page we can make the most of the situation.

How do we work on our communication skills? Well you can either do it as a team or as a solo project. I improve mine through public speaking. I attend Toastmasters and do a lot of reading. I also started by reading some books, take a look here: https://speakorsqueak.wordpress.com/2016/06/03/the-top-3-books-to-read-before-that-next-speech/

Work on your communication skills and you'll more than likely find that your relationships are more rewarding and longer lasting.