My (24nb) husband (22tm) is poly and I am not(?questionable)

Okay so, I think I am coming here just to ease my mind I guess. I found the subreddit and I think this is the only place i could talk about it in a safe space.

So, my husband (we are living together but will legally marry next month!!!! So excited!!!!) is poly and he had always been very clear about this to me and we even tried non monogamy (not just sex but the whole relationship pack) for a while. I had a relationship with a couple (they’re love bombing assholes long story short they were awful to me and treated me like a sex toy) and he was in a relationship (?) kinda with a friend of his. So this is where the issue start. This friend of him is a questionable person, who was triggering him a lot of suicidal ideas and was (apparently, I won’t say for sure bc I can’t be sure about it since i am not him) apparently trying to “steal” all my husband attention to himself. Like if he was on a date with me, this person would get suicidal and he had to run to stay with the person and as soon as he got there he would be fine. We had a fight about it, he apologized for not being aware of it and we closed the relationship.

The thing is, I always think about what he is missing by staying with me. He had told me that if we never open the relationship again he would still be fully happy, and if he ever fall in love we can sit and decide what to do from there but the thing is: what if I don’t ever decided to try non monogamy (that honestly was nice for me, but I would also constantly have panic attacks and my life was already pretty fucked up and idk if u want to find one more uncomfortable thing to solve in life specially in a place , the relationship, where I feel safe in)

Idk if this make sense, idk what I am expecting from this post. I think I am just truly afraid this would , on the future,cost me this relationship I cherish so much. Is any of you guys poly in a mono relationship? Are you truly happy?

Thanks for listening if anyone get until here.