I'm a horrible person

Whoa . . . time is needed to prove to your husband that you are remorseful and want to repair your marriage. You have a lot of work to do in the coming days. Ask him if he will go to counseling with you.

PS___ You really need to figure out WHY you did what you did. Was it to prove something to your friend? (You call that a "friend"?)

May I ask your ages? Do you have children?

Firstly, your life is definitely not over - there's a hell of a lot of living to go, even if at this moment it feels absolutely terrible.

Secondly, as Punkey said - you need to figure out why you did it. Every person has strengths and weaknesses, just has every marriage has strengths and weaknesses, just as every friendship has strengths and weaknesses...what parts of all these factors contributed to your decision?

Thirdly - get rid of your 'friend', who isn't a friend at all, is dishonest, and no doubt has ulterior motives for doing what she did.

If you need time - have you thought of going away for a weekend by yourself? You can put your foot down in this, even if your parents don't trust you - just tell them outright that you need time to think, and they aren't giving you any time or space.

After you come back, you may want to consider counselling. Just be aware it's somewhat of an art form - there are many poor (but well intentioned) counsellors, and enough good ones. Find one that connects with the both of you.

As I've aged, I've more appreciated the benefits of listening to yourself, in whatever culture you are involved in. Alternately, that can cause trouble.

You are between restrictive to the max parents, and your own actions (which need looking at the whys and wherefores).

Stop thinking of yourself as horrible and learn to listen to what you are thinking.
No, don't just jump at any one thought, but listen to yourself.

People make mistakes in life.

It takes two.. Your husband's "best friend" is not his best friend at all, or he would never have crossed any line.

Why don't you tell us how it eventuated. It sounds also almost like a set up to me.. You know, this girl encouraged, maybe even told him, he acted and both don't care.

Is your Husband still talking to this so called best friend?