What are some ways you alleviate stress?

My fiancé and I have hit a rough patch and are stressed out. I found out at a Pap smear I have chlamydia and he recently tested positive too. He's dead set on that I cheated on him when honestly I haven't. My doctor said it can be in your system without being known for years it can lay dormant without symptoms and yes you can test negative for it and still have it depends on the clinics test for it. This has been very stressful on our relationship and we don't want to call it quits either. Does anyone have any tips to help us relax and just move forward from this mess? We have kids as well so alone time doesn't always happen. Can I make him feel more secure about our relationship?