I don't post often but I always swing by and do some reading when mine is off in isolation mode, and it always makes me feel better and less alone.
Miss Amber I completely understand how you feel. My guy can be such a wonderful loving partner and we are incredibly close one day, to completely vanishing out of my life without a word the next. The separation can last a few days, a week, a month... 3 months was the longest so far. We've been together over 6 years. We don't live together, probably never will, he needs to much time on his own.
In a way, it does get easier. You realise they will come back, and that in their way they are coping. The terror that they're going to leave you or kill themselves diminishes every time they don't leave you or kill themselves. And you learn ways to deal with things. You learn that the less you try and communicate, the faster (sometimes) they come back. You learn not to depend on them when they're like this because THEY DO NOT CARE. Not because they are heartless or evil but because they can't care. Their mind and energy are elsewhere. You can't have the same expectations of someone who is isolating as you do in your usual day to day relationship. And trying to guilt them makes things a thousand times worse. There's nothing they can do. It's awful to see someone you love suffering. It's heartbreaking to be continually abandoned. It's psychologically torturous to be in a happy relationship but to know that at any second you could be suddenly alone, for a completely indeterminate length of time.
It does get easier. But it never gets easy. It still breaks my heart. Every time.