Forget the memories?

So I've been in a relationship for about 7 months now. Previously before we got together I was totally head over heels for a guy that wanted no type of relationship with me. Some thing about him always made me come back, I was crazy about him. Despite his flaws I loved being around him. He's a bit of a slut, pardon my French... And that's why I told myself to just stop seeing him. Being in love with him created a lot of problems in my new relationship and it drove us to breaking up a time or two. But we're still going strong. I don't see my old lover anymore. I can't tell you the last time I even had a conversation with him. I was just curious, is it normal to miss someone who was so terrible for your health? I really miss just being around him and hanging out. He always kept me entertained and laughing. Sometimes I catch myself thinking about waking up next to him and watching whatever was on the tv while he was asleep still (he always slept with the tv on) idk I love my current boyfriend but I miss my old flame. Advice?