There are many people here who can give you really good advice, but I'll try just from obvious things. . .

Is your dog a Lab? Is he a puppy? If he is, then there's the answer to your question, "Why now?". . LOL. . if he's around 6-12 months old, he's reaching his bratty adolescent stage and this is what they do! If you're gone for short periods (less than 5 hrs) you can keep him in his crate for that time, if he isn't crate trained start now!! Give him controlled feedings, set the bowl down for 15 minutes and if he doesn't eat he gets to wait until that night. My pup also likes added stuff to his kibble, he usually gets meat, cottage cheese, chicken broth or warm water mixed in. . but he needs to know that if he doesn't eat what you give him, he waits. Dogs wont starve themselves!! Don't feel bad at all, he WILL eat. I also HIGHLY suggest Obedience classes, it sounds like a power struggle is going on between you, your boyfriend, and your pup. He needs to know that YOU are the boss, he cant be allowed up on furniture or beds or counters. NILIF training would probably help him a lot.

If he is a young active dog (guessing he is) he will need more than a couple walks a day. He probably needs around an hour of running and playing in an off-leash area every day to get his energy out, on top of 2 long walks/jogs every day. Try to go home on your lunch break and play fetch with him in the yard or a park, or have your boyfriend do it. A lot of behavior problems are caused by dogs being over-excited and anxious due to lack of exercise. A tired dog is a happy dog =0)