The foundation of your relationship likely had lots of talking and lots of sex. As the silence grows, it is usually lonely for both people. And how each responds to it now will be different, based on who you are.
Not talking and not having sex are often intertwined. Each person makes meaning of the other's actions (or lack thereof) -- whether or not those meanings are accurate. For example: She doesn't love me; he's not interested in me; and further; I'm not worthy, attractive, good enough, loveable, and so on.
By now, sex and talking are fraught with angst, and have become super-charged topics. Each person has been "rejected" enough in their efforts that you don't want to keep trying and getting turned down.
I am going to make a generalization here, and it won't be fitting to all of you: men feel connected through sex; women need to feel connected in order to want to have sex. A note: at times, it is the men who don't want to have sex, so please don't worry about my pronouns.
The 5 Love Languages are touch, quality time, words of affirmation, acts of service, and gifts. Talking and Sex are each languages. Neither is good or bad, better or worse.
Please don't discount your partner's Love Language, whether it is sex or talking. Try to reach out and offer love in each others' languages.
Are there other areas in your relationship where you are withholding? Are you using withholding as a negotiating tool in your marriage? Can you discuss that first? What areas are they? Understanding the meaning beneath issues is so important for couples.
Marriage is not a 50/50 responsibility. It is 100/100. So whoever is able to be responsible (literally, able to respond), please, break this impasse.
So what is talking? What does she want from you? Yes, at times it's talking about your relationship, at other times it is big or deep topics. But in my experience with clients, on a day-to-day basis, she wants you to be interested in her. Ask about her day, show your care, take HER side in the anecdotes she shares, listen well, give empathy, and don't fix.
As for sex, hopefully both of you will initiate it -- but not initiating sex doesn't mean she isn't interested or she's unwilling.
Who initiates conversation? (Not logistical conversations.) Pay attention, and make efforts at both initiating conversations.
Many couples tell me they are too busy to make time for each other. I ask, "If I were a fly on the wall in your house what would I see?" Are you are in separate rooms on your devices?
So make time, initiate conversation, and see what re-emerges with your sex life.