Advice please

Hello ladies

I was with my ex from the age of 15-19 (I’m 20) every year we’ve always come back to each other but never actually got back together. We’ve been on and off for years. Recently he messaged me and started talking to me and because he was my first love instantly feelings raised. If he was fully over me would he be messaging me all the time. Messages are flirty. His only just got into another relationship but it’s the first one since we split in 2017...to me it feels like his still got feelings there. I’m the only one who calms him down even his new gf can’t. Do you guys think he also has feelings?