I think that a good plan would be to be completely honest, tell him why you did in the way that is no placing blame on him, but taking responsibility for your actions. Be prepared to answer all questions honestly and have a plan on what you want to do to save your relationship not just say: I m sorry.
Identify problem areas in you and your marriage and tell him what you intend to do to prevent this behavior again.
Set up therapy.

Well sometimes it's good to let him know that there things you need to tell him. Give him time to absorb that there is something serious to be discussed. I would get child care for the children and be prepared for an up all night emotionally charged talk, fight, inquisition.

Or you may find he goes through a state of shock. My H took many years to build up the courage to tell me. My reaction was shock and I needed a couple of days to absorb all he said. Even though I had very strong suspicions for years that he cheated. I never expected to hear he had a child.

I wish you the strength to get the words out. If you fear you won't be able to get the words out, then write it down and give him the letter. I highly reccomend you find a good mc and schedule a meeting for the day following your telling him. It shows your willingness to work on the marriage and also gives a safe place to talk after he has had a night to think.

I know that my h scheduling mc was a very good thing. We were already seperated when he told me the truth and I was ready for divorce. He hadn't been willing to seek counseling for years so him finding a therapist and making an appointment was a huge step in the right direction. He made sure after the first appointment that I was comfortable with her.

I'm glad you've decided to tell him. The road will be difficult and very bumpy but the path to rebuilding begins with honesty. That is my belief.

the best possible way is to be upfront and honest, when you two have on interuptions, and are both in a calm mood. dont feed it in pieces, but make sure that they have the ability to ask questions as you talk. make sure you do not put hte blame on them and be ready to accept all the blame on yourself.

I agree with all the answers above.

If you have children, ensure they are elsewhere. Things may stay calm and mellow, but probably not and kids don't need to be subjected to the level of intense emotions that will flow.

Being the one to come clean doesn't make the initial cut hurt any less or go any shallower. HOWEVER: down the road there will be a sense of, "OK, but at least my spouse was the one to come forward with this information before I found out any other way."

I assume you are telling your spouse because you want to end the affair and because you want to work things out with him? Really reinforce how much you love him and want to recommit to him and how very much he means to you. It won't really soften the blow, and quite honestly, he may not be able to process that or hear that initially, but as you two continue to work on things, that may be a life raft he clings to.

Be mellow. Be appropriately remorseful. Don't go into hysterics. Don't try to vie for his sympathies - instead offer yours to him.

In the end, it's like cleaning out a nasty wound. It'll hurt like hell to do it and break your heart to be the one to do it, but if you're NOT the one to do it and/or it doesn't get cleaned out at all, it likely won't heal properly in the long run. Better for the pain of cleansing the wound in order to let the wound begin to heal.

The question I must pose.

Is he aware something is going on.

If so the hurt may be lessened, if not the shock is going to be massive.

In my case sought of knew, her admitting was the frosting on the cake.

The second section of this article:

Should I tell?
http://www.dailystrength.org/groups/healing-infidelity-through-faith/news/view/4066000

Is about how to tell. It matches up with some of the advice given here, but gives some more practical steps as well.

Honesty is the best policy.

Why would you cheat - you should start there.

Why you cheated in the first place - you most likely will blame your spouse but thats like a person blaming the victim for their crime. So I would look into yourself and figure out the "why" then once you honestly can openly discuss they "why" without trying to blame your spouse in any way shape or form - approach them and tell them you did this horrible thing - you are extremely sorry - and that you know you need to work on yourself and are in the process of doing that.

well I have being dropping hints to him, and then the words can't comeout.
all week I have felt like crap knowing this.
Im not talking to other guy, told him to leave me alone.
he thinks everything is fine and that it has stopped.
so what do I do, with all the guilt, I have started talking to another guy.

One thing that was always lacking with my ex was his SINCERE APOLOGY for hurting me and betraying my trust. To this day, that has never come--not for any affair he had.

What should you do--here's my advice:

1) Pick the right time talk--don't drop the bomb on him on his birthday or some special day or when he's leaving for work, etc. You need to consider HIS feelings in this.

2) Be sincere in your remorse and SHOW IT. Give a sincere apology, pledge your desire to fix the marriage but be willing to accept the consequences if he chooses not to continue--remember, he is hurting.

3) Get into counseling, both individual and marriage, ASAP! You need to figure out what compelled you to cheat and you both need someone to help you put the marriage back on track.

4) Be transparent. If he asks for passwords, check cell phone, etc. you must comply. You will have to win back his trust.

5) Be aware he will likely be hurt and angry and he may lash out verbally for many months. I remember for a six month period after I found out about the first affair, I carried a lot of anger and I would lash out at my ex. He didn't understand; he felt I should just sweep my feelings under the rug and forget it. That shows that my ex didn't understand the depths of my pain. Understand the depth of your H's pain and realize that when he lashes out, he is working through his pain.

I wish you luck. Building back a marriage is hard work.