My partner of 9 months spends his free time texting his close friend.I cannot see anything sexual to be concerned about but their texts are filled with mutual declarations of respect, appreciation and love.They are very close and confide in eachother. He does not really message her when he is with me, only now and again.They work together every day so I cannot understand the need to be sharing memes and chats, deep and light chats, funny videos in the evenings and at weekends and during holidays. She is much older than him and is married so I am trying to figure out what is going on . He says its entirely platonic.Opinions ?Do any of you have any experience of this please?