I would suggest Al Anon for you. Even though he is a sex addict and not an alcoholic, the Al Anon program will be of help for you. I believe right now you are having difficulty separating the addiction from the man you love.

Even if you don't go to a meeting, google "al anon literature" and have a read. Substitute the word porn for alcohol and see how it goes.

As for the whole snogging thing, forgive yourself. Feeling ashamed over this does nothing, it happened, you made out with your husband.

Stay in contact but meet at a public place, that way, if you feel yourself weakening, you can leave.