Need advice on becoming a step-parent/parent and difference in parenting styles

For a little bit of backstory, my boyfriend and I are in a really serious, committed relationship and we've discussed numerous times the fact that we will be getting married and we will have kids. He already has a kid from a previous relationship who is 3 right now. Although I think he's a really great father, he's patient and kind and loving, he also lacks any kind of authority with his kid. Also, he's a part-time dad so he gets the kid on weekends rather than weekdays.For example, she's 3 and still want's "uppies" and even though he has really bad back pain from it, so much so that it still affects him on the days when he's not even with her. He never puts his foot down and even if he expresses to me that he's tired and he's in so much pain the second she asks for "uppies" he automatically picks her up. It's frustrating to see how he's so unable to put his foot down. This isn't the only issue as well. When she throws tantrums or gets upset, he automatically gives her exactly what she wants, encouraging this manipulative behaviour.The most frustrating thing is I've said to him many times that I don't think this is helpful when it comes to parenting. I do not step in but I just give my two cents sometimes. Every time I bring it up he agrees with me and says it will be different with our kids but he says being a part-time dad makes it hard to enforce rules or be authoritative and when she throws tantrums because it's "emotionally draining." I understand his point but I know for a fact the mother is much more authoritative and enforces rules on their kid and never does "uppies." It's frustrating because he lets her get away with things when she's with him even though he knows he could enforce rules in his own house but chooses not to because it's the path of least resistance.My main issue is that I really don't agree with his parenting style and he claims it will be different for our kids but at this point I really fear that I'm going to have to be the mean parent while he's the fun parent and we might never see eye to eye on how to rear our children. Not only that but I fear that once we get married and I'm the kid's step-mom , although I never want to intrude on the way they choose to parent the child, that I'll have to sit silently and watch him and he just won't take any of my parenting advice.I guess my question is have any of you had really different parenting styles as your partner and how did you both overcome it and get on the same page? via /r/Parenting https://ift.tt/2zBYa0S