The “good” honest, straightforward approach
Choose a public place where neither of you are known as “regulars”, and make a date. My favorite location is a public park. It is very important to choose neutral ground.
Don't make excuses such as “it's not you it's me” or my favorite “I've grown and you haven't”. These sorts of statements are condescending to both of you.
Take a deep breath and tell the truth. If you met someone else tell him/her so. If the spark is just not there anymore, say so. The old adage “the truth shall set you free” applies here.
The honest approach most often ends the lover relationship but not the friendly relationship.
The “bad” cowardly way out
Not showing up for dates is a good indication that you want to end the relationship.
Publicly flirting with others while out with your date can really throw a wrench in the works. This ploy usually leads to an argument, which almost always ends with a scream fest and one couple stomping out in a huff.
And then there is the phone call. Wow. Is that cowardly or what? The only other way of ending a relationship that is more cowardly is the dreaded “Dear John Letter”. Does anyone do that anymore?
The “ugly” relationship breaker
Invite your mother to stay for a week or longer.
Conclusion
Did you see yourself as “good, bad or ugly”? Anyone wanting to end a relationship where both parties are still left with there self-respect is the honest approach. You may just end up with a very good friend for life.