I recently came out of a serious relationship. On Monday, I was doing groceries and one girl asked me out. I thought I was ready to move ahead and should go on a date, so I said yes and settled down on Friday night date. But now, I am feeling that I am still madly in love with my ex girl friend and I need more time to start dating/relationship again. When I called this girl to rain-check/cancel our Friday-night date, I felt that she was really excited and looking forward to a date and I just couldn’t break her heart by canceling it. After looking at her enthusiasm I just couldn’t tell her what I intended to tell. So, should I go on a date and tell her after that or I should just cancel it even before I go on one? Waiting for your ethical suggestions!

Go, have an excellent time. Be a gentleman. It's doubtful "serious" talk should occur on a first date, and if she does bring up stuff, just tell her "that's not first date convo...let's save that for another day."

At worst, your date will be "ok" and you won't repeat it.

At best, you'll actually HAVE a great time. Meaning you'll realize you have the option to KEEP having a good time.

It's a hard road to actually put your life on hold due to deceased relationship and latent feelings. It's crippling if you allow it to be. It is possible to go through that healing time while still having fun and meeting new people.

Nothing serious, it's a first date. Relax.

Your lack of honesty, and your inability to do the right things are appalling, and misleading, and can get someone hurt.

Having said that, going out and having a good time as friends, would do you a world of good.

A few dates is not a commitment, nor is it a relationship. I hope you see how holding on to the past is unhealthy, and makes a normal life, very difficult.

I think the best thing is to go out and have a nice time with her but tell her you are still hung up on your ex (and if you think you might possibly get back together). Don't spend the whole time dwelling on your ex cause that can be a real turn off to another girl that is seriously interested in you and you have no guarantee that your ex will take you back.
If you feel really uncomfortable tell her you feel it is too soon after your break up to start seeing others.

Your not an evil person. Your head is mixed up and you had an unexpected opportunity and you were not prepared.

Id say go, keep things simple and light, and at some point let her know your head is all over the place. She might think this is her opportunity to "save" you. She might just think a date sounds like a great time.