My husband and I keep fighting about the thermostat

One of us is changing the thermostat in our house and I know that it isn’t me. I keep blaming it on my husband, but he says that it’s not him either. Now, if we had children, then this wouldn’t be that big of a problem. You could always blame the kids for changing the thermostat if that were the case. However, we do not have any kids yet and so we know that it is one of us. Either that, or the thermostat is haunted or something. Every single day it’s the same thing. We go to bed at night and our thermostat is turned down to like 68 degrees while we’re sleeping. Then when we get up in the morning, it’s cranked all the way up to 75 degrees! It’s the same thing every morning and we get into a fight every single day about it. We just can’t figure out what the problem is. I’m starting to wonder if there is something wrong with their heating system or if there is something wrong with the thermostat unit itself. We did have our power go out a couple of times about a month ago, and that’s when the problem started happening. Maybe the power surge did something to the wiring of the thermostat or something like that. If it is resetting itself, then I owe my husband a huge apology and he also owes one to me! I guess we’re going to have to go ahead and call our local heating and cooling company then have them come and check out the thermostat for us because this has got to end.

Geo heat pump