I would seek out a sleep school hon. They will teach you about sleep patterns and explain when to night and when to encourage self settling. Do you have the child health line number? I am not sure if I can post it but I will pm it to you. If not it is in the contacts of your red book you would have been given when bub was born.

DD2 was a constant night waker and she did not sleep through till 9months old, but by 6 months we started teaching her to self settle. However at 9 months her waking was only for a feed and then straight back to sleep. Yes I we did let her cry for a bit (not long and not until she was screaming). I stopped talking to her and just kept going back into the room to put her down. I did not put the light on and I did not make eye contact. Actually this worked best when DH did it...So I would tell your partner that her part of parenting is much needed at this time and you need her help...Just because she doesn't feed doesn't mean she can't parent iykwim.

HTH's you....btw this process worked for within a week.