Hi and
You DO have someone to say NO! when you try to eat more than you'd like - you! No other person, whether you live with them or not, can control what you put in your mouth. A lot of people actually find it easier to stay on plan when they live alone - you control which groceries come into the house and what meals get prepared, and no one is "surprising" you by bringing home a pizza or stuffing the cupboard full of snacks.
Do you have an eating plan? Have you gotten rid of all of the junk in your house and restocked with healthy foods? Exercise is a great contributor to weight loss, but it can't do it alone - you also have to incorporate a healthy eating plan.
Look around, find a spot, and keep posting. Can't wait to get to know you!