Advice?

So this will be long but I really could use advice to this situation.

I was in a very toxic relationship for 5 years from 18-22 years old. We lived together on and off, I fell so in love with that man I lost myself along the way. I constantly found out he was talking to other girls, he’d end things w me then we’d get back together the same week. He broke my heart time and time again and I forgave him each time bc I loved him and just wanted to be w him. My mental health became really bad. I always saw his eyes on other girls but I never felt them look at me in the way I wanted them to. I went down a dark path, we got really toxic bc we didn’t trust each other. I’m not proud of who I became towards the end of our relationship. I fought for him until I wanted to end my life bc I couldn’t picture walking away. But I did. I moved to a new state, so did he. A few months go by and we started talking again doing long distance. I flew to see him but ultimately he wasn’t ready to commit like I wanted to w him. It destroyed me. I left bc I needed to, not bc I wanted to. We broke up for 4 months and during that time I got closer to my guy best friend who was strictly just my friend I met when him when I moved. We hooked up and he confessed he was in love w me. My ex tried getting back together w me again and I knew I had to make a decision. I chose my guy best friend to give him a chance. I never gave myself time to heal or move on from my ex. Instead I ignored those feelings despite knowing I was still in love w him. I got serious with my guy best friend and within 3 months of dating we got engaged. Then I became pregnant and we got married. I really fell in love w my guy best friend he is now my husband and he treats me good and I’m thankful that I chose him. My ex tried reaching out to me so many times wanting me back but I blocked him each time bc I knew I couldn’t respond. I never fell out of love w him to be honest. I never got closure, I never dealt w the breakup. It’s caused me a lot of pain since and a few months ago I found out he lost his life to a Fent overdose. I’ve been a mess since. I feel so much guilt bc the dark path he went on after we ended things i feel at fault for. He never touched that stuff until we broke up for good. When I gave birth he messaged me saying how he wishes it was his. Despite all of the pain and trauma from our relationship I never stopped caring for him or loving him. I also feel guilty bc I know this is all unfair to my husband. I’m in therapy working through all of this, including couples therapy as well. We are visiting my hometown to see my family in a few weeks which is also where my ex is buried. I explained how I felt to my husband, that I would like to visit his grave and say what I never got to say, to get the closure I never got to have. I feel strongly that it’s something that I need to do. My husband is obviously upset which I understand. But he says the only condition is that he takes me but I need to do it alone. This will be very emotional for me and I don’t want to feel distracted with worrying about my husband seeing me cry or be emotional bc the situation is awkward and we can’t talk about it without my husband getting upset. I have nightmares weekly of my ex. I feel guilt in my chest every day, I think of our relationship and the pain and guilt I have so many things I never got to say to him to apologize for it eats at me day and night. I’m struggling. I would appreciate any advice on all of this. Thank you .

Also to add, we ended things for good in 2021. So this was a few years ago. He died a few months ago