Hi Kitty,
Welcome to SI, this site is great at helping people.
I'm going to recap your story before providing some advice..
So you started to crush on your H's friend. Found out the feeling was mutual. You two start an emotional affair (EA) through texting. Was there sexting? One night you got drunk and kissed him. Was there any other touching? Was this a passionate kiss? (I'm asking these questions because I'm not convinced this would be a one time thing) Now you feel guilty but not guilty enough to stop flirting...
Now I'm not going to provide advice for you that will assist you on keeping a secret from your H. However I am going to suggest that you need to make solid and firm decisions from here on out.
If you carry on this friendship with H's friend aka marriage killer, this problem is going to snowball BIG TIME. If you want to save your marriage from further pain, STOP FLIRTING ASAP. No talking, no touching, no hanging out because it's Friday night and you guys want to drink beer. It will happen again once your guilt wears off and your guards are let down again. However the next time, it would be more than a kiss.... Dangerous territory you guys are in by staying connected, keeping secrets from your spouses..
There must be underlying issues that you haven't dealt with.. Perhaps issues that you had prior to your relationshiop or maybe in the beginning stages. I think you need to see an IC since you mentioned you don't understand yourself.
Take a glimpse at my 1st post. Some similarities...
http://www.survivinginfidelity.com/forums.asp?tid=462885
I cheated on my H. Thought I could keep it a secret. Originally I thought I could manage the guilt and never do it again. Guilt faded and I found out I liked it and went further down a road of cheating.. Our stories are different after that point though.. However the reason why I'm telling you this is because I didn't deal with my issues after I cheated the 1st time. I thought I was stronger. I wasn't. I was scared to death to tell my H just like you. I didn't see a reason to confess other than relieving my guilt. Some people on this forum might even send you a PM and advise you not to confess.
This is a decision that only you can make however you are on such a dangerous path to ruining your marriage, you must make changes now if your H is important to you.
My decision to confess to my H when he returns back home is not related to my guilt at all. It took me a while to make that decision to confess. The living in limbo on "do I confess or not" was hell on Earth though. Once I made the decision to confess and not look back, it has made dealing with my issues easier.
If you decide to keep this a secret, make sure you don't feel like confessing in a year, or two or 10. It's either a secret or its not. After reading and experiencing through other posters here, their problems have not disappeared, just because they confess or deal with their cheating 10-15 years later. Its waaaay WORSE.
To answer your questions...
How do you live with this as a secret?
I'm not going to.
How do you stop yourself from confessing at a weak point?
For me, I was extremely weak when I was fresh out of affairs. I couldn't bring myself to confess and knew I couldn't do it when I was mentally messed up (hence my user name) Search your soul, build strength, learn about yourself inside and out, go see a counsellor, stop your friendship with H's friend.
I'm about as ready as I can be to confess..
Good luck Kitty. I hope that sharing my story has given you some help?
[This message edited by messedupchick at 6:30 PM, August 6th (Monday)]