Please no negative comments, just need advice.

I have been dating my partner for almost 5 years. He has a teenage daughter that just start living with us within last year. It’s been a roller coaster and a big adjustment for everyone. Our relationship hasn’t been the best within the last 2 years. My issue with him is that he say one thing and does another or just don’t do it which is annoying. When I speak on how I feel, most of the time he will gaslight me and it just leads to an argument but now I’m too the point where I don’t even say how I feel because what’s the point. Me and his daughter have a close bond she’s my little bestie. He also has a mother whom he is very close with. He lets her stay in our house months at a time which is very overwhelming for me. When his mother is in town, he is a different person. I feel like sometimes I always having to compete for his time and attention. Before you go saying “that’s his mom and that’s his daughter” hear me out. For the past 5 years, this relationship has been rough. I have been a yes girl to this man since the day that I met him and I think what you’re thinking “that’s your fault”. Indeed it is my fault because I loved him. But now I’m just tired of sparing my feelings now, I sat back and just let him walk over me. Every time I want to do something it has to be out on hold, but if his mom or daughter mention it he is like yep all for it. I been noticing this for the last 2 years and it’s just idk how to approach this situation with him. Well I kinda tried but he just tells me to leave his daughter out of it and calling me weird about how I feel even though this has nothing to do with his mother or child, it’s about him treating me like I’m a nobody. I really wish I could tell y’all everything and if I did go down the list, y’all would tell me to run as far as possible. He doesn’t even give me reassurance regarding this relationship so maybe I should just end it right? Why not? The only reason I’m only here is because his daughter doesn’t want me to leave since I am a mother figure to her but I really don’t want to be miserable.