How to lower libido

I’m 27 (male) and am currently in a 6 year relationship. She never wants to have sex with me and anytime we are on a date and I compliment her or things start to get intimate in any way she immediately brings up how she has a headache or is blotted or is really tired from work. We have sex 2-3 times a year and only after I beg her for multiple days. It’s like she has to mentally prepare to be with me physically. I’m not obese but I’ve never been known to be good looking. This is the only relationship I’ve been in and the only girl I’ve slept with. I don’t think I could get anyone else to date me and I don’t want to be alone. I’m hoping that if I can get rid of my sex drive then I won’t be depressed anymore. Before you ask why I haven’t proposed in 6 years yet is because I don’t want to marry someone when I hate myself when I’m around them. We get along just fine outside of sex so maybe if I have no libido I’ll want to move forward with the relationship.

Does anyone know any tricks to lower libido and remove all desire for sex without the use of medication?

(We have talked about this several times, she always says she’ll try to find ways to want sex more but nothing ever happens. I compliment her looks daily and try to take her out on dates a couple times a month.)