When we first got a dog, my partner and I were equally involved in taking care of him. We'd go for walks together, we'd take him to the park together. Now, after seven months he has no interest and it's all on me. Our work schedules are different and it's easier for him to walk the dog but he doesn't and I end up having to walk at midnight after my partner goes to bed. What should I do?
Wake him up. Walks are family time. He apparently had an interest seven months ago so get back into the routine.
If he says no, tell him you don’t feel safe going out that late at night by yourself. If he doesn’t make concessions, that’s saying something about his view of your relationship – or of you as a person. And if that’s the case, are you really going to put up with that? If you are, well, enjoy the lonely midnight walks!
If you really want to be a bitch about it, be very, very loud while you're getting ready for the walk so there's no way he could sleep through it. If you live in a house that has an alarm system, set off the internal siren "by accident" a couple of times per week. ("Sorry, I'm just exhausted and pressed the wrong buttons... again. Did I wake you?")
This all might sound petty but, really, is going for a walk with your dog that much hassle? I bet he has no problem committing 20 minutes to watching some kind of screen (phone, computer, TV) in his spare time at home.
Sounds like you’re a responsible person and are willing to do whatever it takes to keep your family happy and healthy. It’s not a one-way street, unfortunately. Well, it shouldn't be, anyway.