As a MiL (in Mumsnet only the male partner's mum seems to be a MiL, but I suppose that is understandable as Mumsnet is predominantly - and quite rightly imo - a site for females), I am appalled by your MiL's behaviour @Ray92. You have not told us one thing about her, or her behaviour, that I can relate to. The way she treats you means that unless, and/or until that changes, she does not deserve to have any contact with you.
Also, there is absolutely no way that your DD should be visiting a house that has someone who is allowed to smoke indoors, living in it. As for the dog faeces on the floor, old dogs can become incontinent, and unfortunately even if their faeces are cleared up straight away, and the flooring is cleaned thoroughly with a safe disinfectant, I would still be worried that the cleaning had not managed to get rid of all the germs - especially if it is on a carpeted surface rather than a hard one. So if your DD is crawling, or at an age when she spends time playing on the floor, then I don't think she should be visiting with either you or your DH.
These points do lead me to asking you two questions, even though I don't see how any potential answers should make much, if any difference, to the advice you have already been given by PPs, but they are:
How old is your DD at the moment OP, and
How far away do your in Laws live from you?
Sorry, I have just realised that your answer to my last question could lead to me asking if they can drive and if they have a car?
I am so sorry that you are living in such a horrible scenario with your PiL, your DH must be very lovely for you to have kept going out with him after you met your potential MiL for the first time! 💐