What conclusions could be drawn from this?

here is the the scenario:

a seemingly nice married man and his wife are good friends with this young lady.

they are a part of a voluntary group. then as time goes by, the man start to be cold towards
the young lady on and off. sometimes he is nice to her than, he acts cold and indifferent.
So she gets confused and start to ignore him as well. but her personality is not as cold as how
he is acting. so most of the time his wife talks to her and is loving towards her. when he does say
something to the girl, he becomes condescending. but when she does a good job in the group work,
he comes over and touch her arm telling her "that was good". then suddenly becomes cold again.
she is afraid to ask him why he is behaving like this. he is actually responsible for making sure the group members are OK...he actually does not make anymore efforts for this girl to make sure she is OK...

then the young girl finally makes friend with a new member who share many things in common.
this new member is a female (older the girl)...so they become close friends as time goes by.

all of a sudden, the man and his wife get closer to her strictly as friends. and completely the man ignores the other young girl. but the wife is still friends with everyone. whenever this young girl is conversation with her new friend, he interrupts her and starts talking to the new member or even calling her over to him in the middle of the conversation...as if no one else is there.

anyway, her new friends seems to be liking the attention, but they are still close female friends.

But if the young girl did nothing wrong and is very good friend with the new lady, why ignore and don't care for her (young girl), as well?

Anyway, 2 days ago he suddenly came up to the young girl and made some sarcastic remark. then after she answered him short answer, he put his hand on her head and walked off. what is going on with him?