Taking care of yourself, as a people-pleaser, isn't selfish -- we just tend to get into relationships, romantic or otherwise, where people get used to us doing everything to please them and then reinforce our feeling of being selfish when we try to do something just for us. I try to keep the oxygen in the airplane analogy in mind: they tell you to put the oxygen mask on yourself first, then on your children or others who need help.
I made a promise to myself, after my divorce and a few other experiences that made me finally realize that pleasing someone all the time isn't good for my mental or physical health over the long term (I'm a slow learner, sometimes), that I will start each new relationship as I mean to continue it. I don't know if you've got yourself into the imbalance in give/take with your fiance, Kera7, but if you have, you may want to choose as a goal one small thing that would move you toward a better balance -- "I will say no to running any errand for him that will take me more than 30 minutes out of my way."
I'm making assumptions based on my experiences -- I hope I'm not too far off. You're a strong and good person -- you pulled yourself back from the brink for the sake of yourself and your children. You deserve to be respected for your feelings, whether someone agrees with or understands them or not.