Relationship coaching

I was thinking about Life Coaching as my niche,but what approach in that would be the best for me?So I tried to research about different approaches in this special niche.
I started my research with making a list of my favourite approaches,in my list I found relationship coaching which was very interesting and usable.
I continued my research by listing different usual issues happening in every close relationship including mother/kids,wife/husband,Friends relationship,etc.
Finally I faced to one of the most destructive issues which is controlling others.
Controlling comes from lack of trust or security.We control others to make sure we have them close to us and never loose them , in other words feel security in our relationship, without considering others rights.
Also we control others because we can't trust to them or to something about them,we don't trust to their abilities,their way of doing things,their perspectives and their thoughts and opinions.
We judge them and destroy our relationship with lack of acceptance.
If we could trust and feel secure in each situation what would be our response to others?