@TWAMSWIAO
I've been in a similar position to you, though we didn't get as far as engagement. We were together for 7 years and I felt unfulfilled for most of it, and envious of friends whose partners clearly loved them. I told myself that our 'companionship' was normal and that romance was something you found in the movies and not real life. Looking back, that relationship messed up my self esteem in a major way.
It all came to a head because I wanted to get married and he wanted to continue coasting along. He didn't really love me and didn't want to commit to me, so he dumped me. I was devastated and felt so rejected, but it's obvious to me now that I didn't love him either. I had just become accustomed to life with him and was afraid to strike out on my own.
I spent almost two years single, in which time my confidence grew and I started to feel like my old self again. Then I met someone who was mad about me, and still is almost four years on. I'm now in the kind of relationship I craved when I was with my ex, but convinced myself it wasnt real. He's excited to plan a future with me instead of stringing me along.
I am now so, so thankful that my ex ended it, as I wouldn't have had the courage to do it. If I had stayed with him I'd be miserable, and I'd have never know what a real loving relationship felt like. Life is too short, don't settle for something that doesn't feel right.