Hi AmyClaire, welcome to the forums.
It is no surprise that you find this situation difficult to deal with. Wanting to experience life with your partner is a normal expectation. Well done for being proactive about your own mental issues but it sure is frustrating that he his doing so little about his own. Obviously his approach is not working and should be changed.
Unfortunately, you can't make another adult help themselves. The problem is that his choice is affecting your own lifestyle and well being. This is an unfair, self-centered attitude. If this doesn't change, you may have to consider whether you wish to settle for more of the same ...or opt out of a potentially toxic situation.
Would he accept research into coping strategies like Relaxed Breathing, Relaxed Body Scan, Mindfulness for example ? Of course, regular practice requires commitment. It is necessary for these techniques to be effective when most needed. Smiling Mind and Buddhify are useful apps. They bring some measure of relief to many people. There's also online treatment for anxiety (MindSpot and MoodGym).
There's a pinned thread in the Anxiety section of the forums :
SELF-HELP TIPS FOR MANAGING ANXIETY
Would he go along with some of the suggestions it contains ? Would he agree to joint relationship counseling ?
If he persists in the despondent attitude, please take good care of yourself and give your options thoughtful consideration. Do you have family or friends support ? Someone to talk to when it gets too much ? If you scroll down to the bottom of this page, you will find a section called Supporting someone, including Looking after yourself.
Good to have you on board.
