evenow

Can I ask how long you two have been together? Any kids? Have you two been intimate regularly? Do you love him and want to work this out?

If yes to the last: if he's flirting with men he may be interested in having sex with men. He might just be curious or he might be in the closet about his desires.

What's most important is you need him to talk to you about what happened. Tell him you can't work on the relationship with him lying. You need him to come clean about where he met this man, why he's been emailing him and what his intentions are about the future. If he can't then there is nothing you can do and he can go be on the down-low with someone else.

If he does finally admit to what you need to know ask if there's anything else (this may be the first time he's been caught!) and make sure you have an idea of what you want from him at this point in time. There are some great references on the board about building back trust. State what you want clearly and make sure he knows the consequences of breaking your trust again. And stick to them. You need to be consistent too that you aren't going to tolerate this.