Thinking about an old LDR since becoming poly. What would you do?

Hi again! Here with a new question to add more drama to my life. 💅

Context: I (35F) spent a lot of my teenage years terminally online (as most latchkey millennials did). In that time, I had an online "boyfriend" who I would be emotionally intimate with on and off over the course of 4-5 years. We'd chat, play games, and talk on the phone (including phone sex). We even tried to convince our parents to let us meet. As we got older we both stopped being online as much until I didn't hear from him again.

About 4-5 years ago, one of our mutual friends messaged me to let me know they had continued talking to him every so often, and that they had hung out IRL. Turns out he was AFAB, and therefore was a girl pretending to be a guy when we were young. I wasn't particularly surprised by this as his photos were always the shittiest quality. But I thanked her for letting me know.

About 3 years ago, he found me on Instagram and messaged me. He apologized for deceiving and ghosting me, and that aside from the gender thing everything had been real. He told me about his current life and that he's FTM. We started chatting a bit more until we realized maybe we shouldn't - I was married with a kid. So we both agreed to say goodbye and wished each other best of luck.

Husband and I have been exploring ENM and now polyamory over the past 7 months or so. This has mostly been casually intimate for us, with no intention of searching for deep romantic connections. We are hierarchical and consider each other primary partners - our marriage and family come first. We're still new and taking things slowly.

But recently, I've been thinking about this old boyfriend of mine.

I want to reach out again. I want to know them again. I want to feel our connection again.

But should I? I'm so worried that given our past emotional intimacy that my husband would become jealous, or unsupportive. I'm also worried about becoming emotionally invested.

TL;DR - I want to reach out to an old online boyfriend but am worried about how that will impact myself and my marriage.

What would you do?