Confused and maybe shouldn't be!

Ok here's the thing I have been in a relationship for 8 years and been married for 5 years! Marriage has been very tough but making it! We have our ups and downs just like everyone else we have struggled to have a good relationship and I'm scared we jumped into marriage when we weren't ready :( but regardless I've tried due to I never want to see the D word! but here's the thing! I have had the same email/ phone # since I could remember! My first love the person who stole my heart to begin with happen to email me the other week. Saying he just wanted to see how I was doing and how I was!! WHHHHHAAAATTT!!! was my first thought he does know I'm married! And says he's not interfering just wanted to see how I was cause he always wonders! I won't lie I will always love him and wish things were different! Now I'm worried because I'm thinking about him constantly and now I'm lost!