Anxious five year old

[fantasyworld]

Not sure if right place to post, have also posted in parenting...
(Not so) DH and I separated nearly a year ago. DD took it very badly, seems a bit more accepting of it now but still cries sometimes saying she misses daddy. He sees her three days a week and he is in many ways a wonderful father, both are trying hard to be civilized for her benefit, however obviously we're human and regularly f*ck up. Anyway. Tonight he came round and we ended up having dinner all together, which we had not done for a while. There was tension as I felt that he continually undermined me in my parenting decisions (e.g. a new chart we've started using; food choices, you name it). Just before he left and while DD was in the other room I made a quiet point of telling him that I was not happy being undermined in this way and that it was unsettling for DD. At every remark throughout the night she kept looking at me with a quizzical look. Needless to say, she was very unsettled tonight. She has also been very tired. I tried to comfort her as best as I could, usual routine plus extra cuddles, allowing her to cry, singing...however it got to a point, as it always does, when I felt that my presence was making things worse and actually she just needed to hit the off button and go to sleep. I told her I loved her, tucked her in and left her to cry for about five minutes, after which everything went quiet. Felt terrible as she kept saying "I want mummy" etc, however I really do think the thing that will help her the most at this point is sleeping...am I insensitive/uncaring? I've never been a fan of letting children crying themselves to sleep (never worked with her anyway), but sometimes I just feel that she is like a laptop that needs to be force shut, excuse the crude analogy...