I don't think the concentration is affected. He's talking less with me, but I think that is partially justified because it's a new relationship with her and it does need time, but to some extent she is also being overly demanding. She would keep him on the phone all night until he was falling asleep, every night. I told him he is blind and that she is doing this because she just doesn't want him to come sleep with me, because she is jealous. He didn't dispute that. He literally would come to bed and fall asleep in only 10 seconds.
On the other hand, he does seem to have a warped sense of time. He told me one time "I only talk to her 1-2 hours a night" when it actually was 6-8 hours a day. I had read that people do sometimes misjudge time when they are in MLC and so I didn't bother to correct him on that ridiculous point. And he also said, "but I spend all day with you" when actually I mostly saw him for 2 minutes at a time when he came in and out to get something or change his clothes, but that was not due to a lack of attention span, just that he was busy.
He's very busy with preparing the home for her and his work. I'm not going to say what he does as I want to keep my identity obscured here but not only do his customers come to his workplace, he's got them coming to the house on the weekends and sometimes at other times so he might lie down for a nap and have to get up again in 2 minutes because someone shows up. We recently moved to where we are now and we had our home to ourselves all the time before even no visitors so it is a change.