Stop contact with that person NOW. If you feel that an EA is starting, stop it before it begins....NOW.
If you do not then you are not focusing all of your energy on fixing your marriage....because there is a part of you reserved for thinking about this "friend", who looks forward to seeing/talking to him etc. That energy needs to go towards your H and your M.
You have a HUGE warning sign in thinking that "the EA is starting I feel." Nip this in the bud NOW. You should most absolutely NOT be sharing intimate details of your marriage (and problems within your marriage are included in that) with ANYONE of the opposite sex unless that person happens to be your therapist.