Guy friends while in a relationship?

I believe that in a relationship you shouldn’t do things that you would be bothered by if your partner did it.

I cut off all my guy friends for my boyfriend, but that was my decision and I didn’t care. My boyfriend did the same, also his own decision and he didn’t care at all. It’s been completely fine until now years later I am really missing one of my old guy friends. He was good at giving me advice, he was there for me during the hardest times in my life (that my boyfriend wasn’t present for we didn’t know each other yet), and we would laugh all the time. We just had a different connection than me and my boyfriend, but that doesn’t mean that my boyfriend isn’t amazing in his own way. Just different bonds you know?

I feel like if I were to reach out to this guy friend, then I’d be doing something that I would be upset by if my boyfriend did the same. I don’t have any romantic feelings for this guy, he was just my best friend, but I think I would still feel guilty.

*Adding that me and my guy friend did have sex years ago, but we decided to just be friends, and I miss him as only a friend.

What do I do?