Is this wrong of me..?

So my step sisters ex boyfriend is still a good family friend of ours. They dated for 5 years, and he was pretty much family to us, and she ended up cheating on him, kicking him out, and just all around treating him really poorly. She’s now engaged to that guy she cheated on him with. But it’s been about 3 years, and my whole family (besides her obviously) still talks to him. Because again, he was family to us. He was around more than she was for a long time, bc she was in school far away. He is in law enforcement and has helped me with my career a TON. I’m getting sworn into my local sheriffs department next week, and I’d really like to invite him to my ceremony, but my step sister is going to be there. Is it wrong of me to do that? She was very angry with us when she found out we still spoke to him, which I can partially understand. I don’t want to make her mad, but he has helped and was there for me a lot. I’d really just like an outside opinion.