Why the hell not if he won't find out and they aren't dating? It's not like she or I have any responsibility to him.
Your concept of friendship is strange. Friends have mutual responsibilities to not be shitty to one another. Because he might find out, and then he'd be hurt, and you'd be a shitty best friend. Or even if he didn't, you'd feel weird hiding it from him, because of the dishonesty-by-omission. But it sounds like you're going to do it anyway.
You've clearly either done it or made the decision to do it. If you're hoping to find someone here with "loose morals" to support you (and it's "loose", by the way - not "lose". Unless that's a Freudian slip on your part), I don't think you're going to find what you're looking for. It makes you, at the very least, the shittiest friend on the planet.
Ah, Shame vs. Guilt. Ask yourself this: if we had told you that what you want to do (or have already done) is OK, would that have made you feel better? Would a bunch of complete strangers validating your choice really have cleared the air for you? If the answer is yes, consider what that says about your code of ethics.
I won't lie, I am just a bad person in general. I had a whole bunch of justifications in my head, but obviously you can't take stuff like this to other friends. Drunk me needed to throw it out to someone. Who better than a bunch of anonymous people on the internet?
No, you're not. That's a justification, not a reason. A bad person would have fucked her already. You want someone to tell you it's alright. That's not the sign of a bad person. It's the sign of a weak person.
Maybe just consider it when you're sober. Although, if you are sober and you still want to do it, the answer is no. The fact that you need to think about it instead of doing it should show you that you know it's a bad idea. It's just... not cool, I guess. Just not cool at all.
Who better? Depends on the answer you want. You can't take it to your friends because you already know what they'll say. You pose it to us on the off chance that even one person here gives you the go-ahead, and then you use that as permission to do something you know is objectively wrong, but are willing to do anyway if enough arbitrary mental boxes are checked off.
Even I wouldn't do that, and I'm the girl who put up an internet dating profile a day after breaking up with my incarcerated SO out of childish spite.
I just got back from a drive from Las Vegas that should have taken nine hours. It wound up being twelve hours as I-15 had two separate wrecks blocking both directions on all six lanes of traffic. Did I mention the summer thunder rain squalls at the same time? I had promised myself not to drink tonight as I have busy day tomorrow, that was six dos equis ago and I just discovered 33 pages of drunk thread to read. Looks like it is going to be a long fun night.