I guess it really comes down to why one feels a relationship is coming to an end. Sometimes it's a matter of lack of communication where both people appear to be going along to get along without truly being engaged. In other instances they're simply spending less and less time together.
And last but not least one has a feeling their mate is seeing or interested in someone else. The reality is (one person) cannot save a relationship. Both people have to want to be together.
Honest communication is the GPS for relationships.
It lets you know whether you're "growing together" or "growing part". Sometimes we opt not to talk to avoid making what we suspect real. Nevertheless talking about it is the best shot you have at seeing if there is anything left to hold onto.
Once everything is out in the open at least you'll have some clarity.
"Never love anyone who treats you like you're ordinary."
- Oscar Wilde
If someone doesn't want to be with you they don't think you're right for them. Thankfully there are over 7 Billion other people on the planet. Odds are in everyone's favor there are more than a few people who would make ideal mates for each and everyone of us.
The goal is to be with someone who loves and appreciates you.
Every ending is a new beginning!