That is up to him. Some people can, some cannot. I, for one, dont think I could trust again.

Are you willing to look at why you did it?

I think I did it because I was having second thoughts about getting married to him.

Whether he should forgive you is up to him. Even if he does forgive you, that doesn't mean he will want to continue in the relationship. Forgiving a person doesn't necessarily mean they still want to be a part of your life, that's something he needs to decide.

I agree with Peterpaul, having second thoughts about marrying him is an issue in itself. It's still not an excuse or reason to cheat.

I think the real issue here is that you really don't want to marry him, I think in some way you have not been happy in this relationship and that is why you cheated and why you smoked pot.

Find out what you really want.

We talked and are going to try to work things out. I know I said I was having second thoughts about marrying him, but I never had second thoughts about being with him. I just wasn't ready to marry him. I love him so much and am so glad we are trying to work things out.

He found I cheated because he asked if I had ever cheated and I told him.

You need to make sure you get this resolved before you get married. He will probably continue to have serious trust issues with you and you'll have to deal with that. It won't be easy for either one of you.
You need to know and remember that when you cheated to inflicted serious damage to your relationship.

i would wait to get married for another year or so. There's a reason why you cheated and smoked pot. You need to talk to someone about this to get this resolved.

He should have second thoughts about you now. You cheated because you werent sure about marrying him?? So you had to go look around for someone else just to see if he is worth it or not? Yeah, thats not very good for a relationship. Seems you fear settling for less and want to have your last minute freedom. In that case, why marry? Go date and have all the sex you want, get it all out of your system. And maybe down the line if its not too late you might get married without any inhibitions.

I agree with the others. Whether he decides to forgive you is up to him and his personality. Trust is a vital part of a healthy relationship. Once trust has been broken there is permanent damage that has been done to the relationship. You can forgive and move on, but you will never get the trust back to the point that it once was. That, in and of itself, is usually enough to prevent a relationship from being healthy and successful if one of the parties has broken the trust of the other. You broke his trust at least three times ... once with cheating and (at least) twice with drug use. I may be able to work my way past a single cheating issue. The drug thing is a BIG deal for me. I watched my older brother destroy his life with drug addictions (starting with marijuana). My ex-wife chose to start drinking again even though she knew that it was a deal breaker for me.

Talk to him, find common ground, and look inside yourself and determine if you can be happy in the relationship with the agreed terms. Not everyone is willing to make the necessary changes to be in a relationship.

I don't want to sound nasty but I think you are being very selfish- SHOULD he forgive you? No I don't think so- instead of talking to your guy about how you feel about getting married, you made the choice to go and cheat on him. What you did is devastating to a person, you hurt him on the deepest of level for what ever reason. This is something that just doesn't go away- even with time, my may be able to forgive you- trust is another thing. This sort of betrayal has life long effects, he is probably wondering what HE did wrong, why wasn't HE good enough etc. It's damaging to ones self esteem to say the least. You have taken away his trust in you and his confidence in himself and your relationship. Were you thinking of him when you were with the other guy? Did you stop to consider how hurt he would be? What about this other guy? Were you just using him and not worried about how it might affect him too? You also only told him because he asked you- so you kept it a secret for 7 months- which means what?

As somebody who has never cheated on anybody no matter how badly I was treated I am probably biased when I say this but...I don't know if SHOULD is really the right question here. CAN he forgive you, WILL he forgive you? Those things are up to you but SHOULD he? I only know I wouldn't be able to. It's up to him if he decides he is able to or not. I note that your follow up post says you two have decided to try and work it out. I would keep in mind that while he thinks he might be capable of moving on from this, he might decide down the road that he just can't get past it. I have witnessed this first hand with a cousin who cheated on her guy. He did the valiant thing and tried to forgive her and stay with her for the sake of the kids but in the end it slowly ate away at him to the point where he resented her and finally divorced her.
And I thought a good point was made by those that said if you were doubting the marriage idea in the first place than that is a problem in and of itself that you need to take a closer look at.

Relationship counseling BEFORE you get married. You need to sort your feeling out. Trust me...Been married to my HS sweetheart for 13 years and cheated online at 10. The reasons you aren't sure aren't going to go away. With kids and stress they are only going to intensify. Better to deal before than to deal with the aftermath after 10 yrs of marriage and 2 kids.