Romantic relationships: How does one end them "correctly"?

Luckily, this is not a problem for me at this time because I'm very happily married. However, I have a problem that I'd like to try to understand. I'm in my mid-40s, and I've had three romantic relationships. Each of the first 2 lasted 9-1/2 years. It seems that once I'm in a relationship, I can't get out because I'm afraid to hurt the other person. In both of these relationships, I pretty much knew a year or two into the relationship that it wasn't really what I wanted, but I was stuck because of my over-sensitivity. A part of it is that I just don't want what I would think would be bad karma for causing so much pain to the other person. However, I also felt as though my heart would break -- I just couldn't bear inflicting something like this on someone that I loved (but was not "in love" with).

I know that I wasn't being true to myself by staying in these relationships, but I consciously made the decision to stay to avoid traumatizing someone else. Has anyone else been in this situation? I have to admit that I'm extremely empathic. Is there no hope for me? I hope that it's a moot point for the rest of this lifetime given my current happy relationship. However, I don't want to continue this pattern into my future lives as well.

Any thoughts?

Thanks for any light that you can shine on this dilemma.

I learned this the hard way. If you know the relationship is wrong, that you don't feel the same way about him that he feels about you, the kindest thing to do is to let the person go and let him find someone who will love him back. It is wrong to claim that you are staying in the relationship in order to spare the other person's feelings. If you do that, you are actually staying in the relationship to spare your own feelings, to avoid an unpleasant scene where you think you may end up looking bad.
You must find kind, loving words to let the person go but you must let him go.