Oh, hi! I'm extremely sorry for answering only now but lately I wasn't feeling focused for a similar ask and I was busy between studies and stuff, I'm extremely sorry, adorable anon, to make you wait!!
First of all, you aren't lying to yourself or your partner. Masturbation can be something completely different from sex, you could search masturbation but not sex and vice versa. You could need masturbation because you prefer a self-exploring moments for yourself while an intimate moment with someone could require you more energies. It's totally fine! Don't feel guilty for what your body is asking to you, it's perfectly healthy! So you aren't false, you are just yourself ^^
Here there are other important questions: does your s/o respect and your needs? Do they understand that you prefer masturbation but that this doesn't mean you are less interested with them? Are they respectful? Are they okay with this? If they are fine, then there is no problem! ^^

I'll say this, even if it's personal. I always had a higher libido than my bf and also more need to sex (in our case sexting or sex calls). I used to get angry with my bf when we didn't have sex after a while but now... I understand that I wasn't acting right, especially at being so aggressive and needy. Now I feel less "aggresively horny", but I still jerk off a lot, at least once a day, and when I feel like I need sex I ask to my bf and I feel happy when he wants to do it, otherwise I understand when he isn't in the mood. It really depends, but the important things are boundaries and respect.

So the important thing is your s/o respecting you because there is nothing wrong at having a weaker libido or wanting sex only in rare occasions! Don't feel guilty about yourself, anon!! Sorry for the late reply, but I hope it can help you a bit, I wish you a very wonderful and relaxing day!! ^^