I am at my wits end, I have been with my partner for nearly 3 years and am in a three-way relationship where I am the third wheel. I have my own house and my partner has his. Due to a change in my circumstances, I am struggling to maintain living in my house (which he says is nothing to do with him) and thought that after 3 years together we should be thinking about moving in together. However, I am not the "partner" in our relationship (or at least that is how it feels) and my needs and wants are not important. His now 18 year old daughter currently lives with her mum but spends most of her time at weekends at his. He has recently come into money and is looking to buy a big house. He is doing this mainly because his daughter wants to move in with him and her room in his current house she feels is not big enough for her (it is a double room). She gets a say in what house they buy and is finding properties she likes and going on viewings with him and if he likes somewhere and she doesn't then that is it! She has just said that she thinks he should up his budget by about £50k so that she gets what she wants in the house. She has a say on everything in his life - what car he has, what clothes he buys / wears, where they go on holiday, where and what they eat, what he spends his money on and what they do at weekends. He pays for everything for her (even though she has a part time job) including her hair, her clothes, her make up, her toiletries, her tattoos, the fuel for her car, her car itself, the car insurance, the modifications that she wanted for her car, the new ipad that she had to have, expensive weekends away, expensive holidays, festival tickets - the list goes on. I don't think she likes me much, sometimes she barely acknowledges me and if me and my partner go out without her, she asks him how much he spent - and he tells her! It is like she feels that he should spend all his money on her and nothing on me (I do always pay my way but my financial circumstances are not great and nowhere near as good at his). When there is the 3 of us, they walk together sometimes arm in arm and I tag behind. On holiday, he will sit with her and I sit on my own and we have to do and go where she wants. I just think that she has too much control over his life - it is everything (he will go and change if she tells him to and will buy clothes because she tells him too) and he asks her opinion about everything and takes it fully into account. When they get "their" house, she will be choosing all the decoration and they will live together in harmony, cooking together, doing everything together. My question is, where does that leave me?? I feel like the third wheel and not a part of it and I want a proper relationship, one where I am the "partner" and treated as such - is this wrong?? I am not getting any younger and don't what to waste anymore time on a relationship that isn't going anywhere. He can't see it and says that she will get whatever she wants and that is the way it is and she will come first (which I understand but not to this extent) and he will get the house she wants, will always buy her want she wants, do what she wants and spend all the time with her that she wants (which is a lot as she does not have a lot of friends at all).
I would welcome thoughts as it is affecting my mental health terribly and I am on a downward spiral as I am so confused. I thank you all in advance x