Why am I feeling this way? Is it bad, normal, or both?

So this weekend I ran into an old friend of mine from my undergrad years. I have known him for a long time and way before I met my husband. I used to just have a little crush on him, but we never were anything more than friends (bffs). And just this weekend like I mentioned earlier I ran into him while I was with my husband (yes I introduced them/my husband knew about him before they met) and we talked, told my husband a couple of stories and then we said by to each other. And after my husband and I went on with our day. But ever since I ran into him my old crush came back but not as strong as before because I know in my heart I love my husband. But why am I feeling this way for my old friend and is it bad and will it go away?

Ps i don’t have his number or any of his social media’s and also up until this weekend I hadn’t seen him in like 3 years.