I wanted to get in touch as I experienced a similar situation with my partner a few years ago. We had been together for nearly 8 years, and I had noticed he was sleeping more and becoming really distant. I confronted him about it, and he said he didn’t love me anymore, and also fixated on things he had said previously. This came out of the blue in one sense, but looking back, I now see the signs of depression. I wrote him a really long letter, just saying everything I felt, and telling him how much I love him. After a few very intense days of talking, and a week of living apart, we realised how much we wanted to be together, and that he needed to seek outside help for his inability to address his emotions.
I have to say, he was quite reluctant to seek help, however, I told him that we could not go forward without him speaking to someone at least once. Thankfully, that gave him the gentle nudge that he needed, and he did come home after the appointment, saying it had helped. I didn’t ask anything about it, but just told him how happy I was that he had done it. He went for a further 3 sessions, and from there hasn’t felt as though he needs it anymore.
Our relationship has gone from strength to strength since!
I’m really hoping that this helps you with your situation. At the end of the day, you need to strive for your own happiness, and if your partner is part of that, you will obviously want to include them. Hopefully they will be open to speaking to someone. It honestly saved my relationship! Good luck!!