It’s becoming difficult to keep in contact with my 13-year-old son

I am a separated father and have one son who will be 14 in December. After a challenging time when we first separated, his mum and I now get on well and both of us are in new relationships.

I live a good bit away and the routine is usually that my son stays over with me every second weekend and I phone him two to three times a week. The trouble is that it is becoming more difficult to keep the contact with him. He doesn’t talk as much as he used to and sometimes he is reluctant to come to the phone.