Whining

Im thinking about getting married to this guy soon, however, there is one thing that is holding me back. We are not on the same page when it comes to giving in to my daughter. We just recently moved in together and im glad we did because I don't know if I like his co-parenting style. Whenever I tell my daughter, for example: No you cannot play with your 4 wheeler,he steps in and says, "oh come on 'Oscar the Grouch' she's been good today." I can't help but to get frustrated. I feel like this has really been affected how she acts. She has now been whining and pouting everytime I tell her no. I don't think that this is just her being a typical 5 year old. I have never had any problems like this before. I know it has something to do with us being on the same page; we are'nt and its frustrating.