6 year relationship intimacy issues 25F 29M - getting married in 3 weeks

TLDR; partner doesnt view sex as a priority and tells me to be ok with it.

29M and 25F have been together for 6 years getting married in a month. We have had sex issues most of the relationship - mainly regarding the frequency and the amount of enthusiasm on her part. Fiancee has a IUD for about two years now, kind of coincides with the issues I am discussing from my point of view, expect she stated today that its always been like this and she just gave me what I wanted earlier on in the relationship. I found that a little deceptive and was somewhat saddened by it, because i really believed there were a lot of genuine times where she loved it, as she initiated a lot of stuff.

Sex had been good at first and she was more adventurous and horny. She moved away 2 years ago for work and we only saw each other every other week for the weekend. Intimacy, dirty talk and flirting reduced significantly and it had even reduced prior to her koving away. She was less adventurous than she was early on when it came to sex acts as well as locations - we previously would have sex frequently at home, she would tell me how shes horny and wanted me, would text me that she lusted over me and would tell me how wet she got when i touched and kissed her. We would also have risky outdoor sex and try different positions and she would wear sexy lingerie etc., nothing too crazy like bdsm or anal even though she likes some anal play.

She has since moved back and we are getting married in three weeks. I spoke with her today and just mentioned how sex and being intimate/horny, touching and flirting dont seem a priority for her and she agreed that it wasnt and told me that i needed to adjust my behaviour and needs. I told her it was sad that she viewed it like that because i am already not receiving what i would like and find it really hard to know when she wants something and when not. I asked her to try and get in the mood of being horny somehow by being more comfortable being turned on alone and masturbating/watching porn, so that she could bring that attitude into the relationship. She was very reluctant and became defensive and told me how i could do more to make her want me which I find hard to achieve.

She told me that she finds it hard to look sexy and be flirty and touchy with me as she doesnt always want it to lead to sex and says i should accomodate this. She says she doesnt dislike it but just has other priorities that are more important. I told her that were together and the relationship is a priority and if i say that i feel like theres an imbalance, she should try and improve rather than expecting me to be fine with less or telling me that i need to somehow get her in the mood, which is impossible as its not a priority for her.

We have sex like twice a month currently and its a chore. She has issues with her body where she is one not very confident in her appearance despite looking great, she is currently exercising. And two the fact that her skin gets very itchy which doesnt help with kissing; either my beard scratches her or my kisses are 'too' wet, which means she only want small pecks which is not sexy at all and she just lies there and im so not into it which just motivates me not to initiate anything with her. Sometimes i can kiss her neck and sometimes i cant. Its really confusing. She also doesnt like the sounds mouths make when kissing. She says i slober all over her face which isnt true but i would agree that it probably feels like that to her especially when youre kissing with tongue/breathing passionately during sex around her neck.

I love her but this situation is extremely hard to deal with. I really just want her to try together with me to improve the situation rather than always telling me that I am the one that needs to change my behaviour even when I am not intiating sex with her (she turns me down when I do anyway), dont kiss her, look great for her a lot of the time, am not touched and when we do have sex I just do basic stuff and its boring and it feels like going through the motions - there is no passion. Ive already lowered everything and am not happy/coping with it. I wont cheat because I love her but I dont feel like I can be happy in this type of relationship. I need my partner to want me. So i feel like if shes serious about the relationship, she should try and be interested and occupy herself with it and treat it as a priority.

After arguing for a couple hours she came around reluctantly but i just need her to be serious and want to improve and not just settle as Im in a relationship with her and were a team. I want her to want me and if she cant then maybe we arent meant for each other? Im really confused. I love her but it just feels like the sexy adventurous spark is over but were getting married very soon and i actually have no problem other than this. Depsite her displaying similar behavioural traits of reluctance to cooperate with other things, but they just dont bother me as much.