Mysteriously Stopped Eating! I'm stumped!

I have a six year old corn snake who has mysteriously stopped eating. Everything is the same as always, same tank, same food, same feeding rituals. He has always been a great eater, and eats about every ten days. I feed him adult sized frozen mice. He is really active right now since spring has started. He's moving around the tank a lot. He gets really mellow during the winter which is pretty normal. If anything the tank is warmer now because of spring. But I have a 20 gallon tank and one side is cool and one warm so he has options. He does not seem agitated when handled. (he's a super mellow dude) I do have a cat that sometimes hangs out, but that has always been the case.

He is not blue. He already shed once during this no-eat time. He doesn't appear to have anything wrong with him that I can see. No mites, no breathing problems. No discolorations. I have cleaned his tank and am being meticulous about keeping his water fresh. He did have a respiratory problem a year ago and I took him to the vet and he got antibiotics and recovered well. Since then I've been more regimented about cleaning and keeping his bedding dry. Maybe he has a mild version of the same thing - asymptomatic? That's the only thing I can think of.

I have tried feeding him in the morning and at night. I've thawed his mice in water and just in the air. I've left the mice in the tank for longer than I'm comfortable with honestly. I'm not sure what else to do. It has been approximately 1.5 months since he has eaten, which seems a little long! I've thrown out so many mice!

Any ideas what the issue might be?

My guess is that Spring is in the air and he is looking for a mate. So food is WAY down on his priority list right now.

I would concur with Rich. My male finally ate this week after refusing food for 2 1/2 months. This happens every year in the spring so I imagine you can expect the same thing to happen next year as well.

Yup, sounds like extremely typical male springtime breeding behavior! Nothing you can really do about it, unfortunately. I would simply offer him food once a week. You might have success using a smaller prey item, like a fuzzy or hopper, heated extra hot and brained.

Wow thanks everyone! I had no idea my snake was horny! Now I have a fun story to tell at parties.