24M struggling with emotional and sexual disconnection from 24F girlfriend of 1.5 years—how do I handle my needs without pushing her away?

I’m a 24M and my girlfriend (24F) and I have been together for about 1.5 years. We started dating while she was doing her master’s and I was still in my bachelor’s. A month into the relationship, she went to Spain for a semester abroad (Erasmus), so we did long-distance for a few months. During her visits, things were good emotionally and sexually, but I noticed that during our video calls she often felt distant—sometimes sad or disconnected, even if things between us seemed fine otherwise.

After she returned, we moved in together. That’s when I noticed a decline in emotional and sexual intimacy. She still had two more semesters—one more relaxed and one focused on writing her thesis. I stayed in school for my bachelor’s, so we were at different life stages. Sex dropped to maybe 5-6 times a month, sometimes less, and emotionally she became more withdrawn. I felt like I was trying to maintain closeness while she was retreating, though I know she was under pressure with school and life changes.

She recently opened up and told me she’s been feeling this constant emotional heaviness—not tied to anything specific, but always there in the background. She said she feels judged or not good enough when people try to help or give advice. She also said she doesn’t want to talk about it much and wants to deal with it on her own. I suggested therapy gently, but it triggered her and made her feel worse.

Now she’s moved back to her family’s home and is looking for jobs, but she’s facing rejection after rejection and is really down. We’re back to long-distance again. Since all of this started, I’ve felt emotionally and physically disconnected. I have a high sex drive and, while I care about her deeply, I’m starting to feel like I’m running on empty. I’ve been trying not to pressure her, but I’m bottling up my own frustration, and recently I’ve started feeling attracted to other women. I haven’t acted on anything, but I’m feeling torn.

My question is: How do I respectfully express my emotional and physical needs to a partner who is struggling with what seems like depression, without making her feel worse or judged? How do I know when I’ve been supportive enough, and whether it’s time to take care of myself and consider walking away?

TL;DR: 24M in 1.5-year relationship with 24F. Things were good at first, but since we moved in together and then went back to long-distance, emotional and sexual connection has dropped significantly. She says she’s struggling internally and doesn’t want to talk or seek help. I love her, but I’m emotionally drained and unsure how to express my needs without hurting her. How do I handle this?