Advice on dating someone who’s stressed

My boyfriend and I haven’t had sex for about a month. He’s been really stressed and sad because when we first got together I was extremely depressed and he had to help me through a lot. He says I’m the first person he’s ever loved and truly cared about. He said he was never really sad until he met me because I made him feel things. Any advice on helping him be less stressed? He gets really upset over little things and he never used to be like that. I try to be as kind as I can and I always do things for him like rub his back or write him paragraphs.