Welcome Kristian,
Come and air your woes any time, at some point I expect most of us have been through a similar experience, no-one is here to judge.
How old is your daughter? I'm guessing pretty young as you say she has stopped breastfeeding, the first year or so can be a very hard time with a new baby and can cause a great strain in any relationship.
I will offer my own general advice as an outsider.
1. talk to eachother, when the kids are in bed - asleep, just talking through how you feel with eachother can have such a positive effect, both of you are adjusting to having a little one, agree before the talk to hear the other one out and not judge, you may be surprised what you learn from eachother, for example your partner may just want you to change a nappy now and then, but because you dont everything else is exagerated and the knock on effect continues because her back is already up (not saying you dont change nappies, just an example of how something seemingly trivial can have a knock on effect to everything else), also your partner may not be aware that you feel like everyone else has more say over your daughter than you do - tell her calmly, it may just be that because her and everyone else have had babies or used to babies being around they automatically take over without realising because you have no previous experience
2. is your daughter sleeping through the night? if both of you are up every night at all hours and having continued broken sleep this will put a huge strain on everything else, even the simplest things become such a chore and arguments from nothing will occur, there is a reason sleep deprevation is/was a form of torture - it can ruin you, depending on your daughters age it may be time to teach her to sleep, possibly look into the controlled crying technique, some people disagree with it but i can tell you it was the best thing I ever did when our son was about 9 months old (it has to be done properly - speak to your health visitor or buy a good book), after a week he slept all night with no feeds and has continued to do so without any problems at all..he is 2 next month.
3. maybe your partner is suffering post natal depression, this can easily go unnoticed for a long period of time - might be worth looking into, read up on it, talk to her and support her, maybe if she is happier everything will stop being your fault!
as mentioned relate is a valid option.
whatever you decide I wish you all the best and good luck, come and chat any time.
Regards
Danny