Hi EmilyAnn,
You really need to snoop, ASAP, but it may be more difficult now that you have confronted your H. He may be covering up even better now. The advice given here will change IF an affair is the issue. Sudden change in behavior/attitude and wanting "out" typically indicates an affair. Dr. H advises snooping!
He also gave the well known I love you, but am not inlove with you type speech....red flag...this is such common WS wording.
Many of us here (myself included) have had to deal with a secret affair in the past.
My H had a sudden behavior change, gave me the ILYBNILWY speech, of course did NOT hint of an A, and was heading for the door. We also had several long talks. I was so confused, and tried to make sense of what he was saying and tried to go about fixing things. I didn't know about MB, but did wonder if he was having an A. I turned to my closest friends, they felt NO AFFAIR, based on what he was saying.
I decided to do some quiet snooping anyway, at that time people were not so internet involved, with phones, facebook etc. so I did old fashioned snooping. I waited for him to be fast asleep, searched through his car with a flashlight, and took his wallet in the bathroom and examined all contents. I did find a clue in his wallet, but not a smoking gun. Then I made a major mistake and called his family to fish around. This alerted him to my suspicions, and he went further underground.
Today the computer and his phone are the best place to start. Check facebook, emails, txt messages, incoming and outgoing calls, internet history etc.
You can also contact the Harleys, if you are not sure.