I have many friends who when dating struggle to determine if their potential interest is a "good match". Prior to meeting my wife, I was advised by a mentor to create a "mate must" list. The list essentially creates a series of items you desire in a potential mate. Some of the items may be frivolous such as "hair color or weight" - while others may be non-negotiable such as "must love kids" if you have a child. The list will help you tangibly evaluate a date by issues that matter to you.
I believe a healthy relationship is when you can look at the relationship and honestly say you are happy at least 80% of the time. If you you aren’t then maybe it is time to move on.