Housebroken Dog 'Going' Indoors

Hey all,

I'm relatively new to dog ownership [less than a year] but my rescue was previously housebroken and did not have any issue adapting to her new environment. Until about two weeks ago, she had only gone to the bathroom [urinated] once, and she went on the linoleum kitchen floor [which I quite appreciated].

In the past two weeks, she has started urinating or defecating in the apartment almost daily [and sometimes both]. Her walk/outdoors schedule and diet have remained the same [in fact, her trips outdoors have become much more frequent]. It seems to happen when my roommate and I are not home, or if we are asleep. [She used to wake us up for 'emergencies' and, considering how infrequent they were, we'd take her outside].

My initial thought was an infection or sickness, but I just paid my veteranarian $300 to find out that there is nothing [systemically] wrong with her. Either way, there was a viscous, opaque discharge from her female parts the other day, so I still haven't ruled out a urinary tract infection. We are treating her with appropriate antibiotics and it has cleared up her nether regions.

I'm trying to think of more relevant details. Ah, I did pick up a second job recently bartending a few nights a week. Obviously this may suggest that her problem may be psychological [she is my dog, though my roommate does also take care of her]. Again, while I am definitely home less, my roommate's schedule remains the same and there is little time that she is currently unattended where she would have been attended in the past.

Finally, there is the biological aspect--if she smells **** or piss, she'll continue to **** or piss. I've professionally cleaned my carpets twice since the event, most recently on Tuesday night. That said, I came home on my lunch break to find two large piles of **** in the living room.

For what it is worth, morning and evening walks do not end until she has defecated, and she does go outside for extended periods beyond these walks. I would say she gets an appropriate amount of exercise [if not in excess--my roommate and I are both runners and we regularly take her to the largest dog park in the area for canine camaraderie].

Beyond using the living room as a toilet [and it tends to be in the same two areas], she's incredibly well-behaved. I have no qualms with her being off-leash even in relatively busy areas.

I would prefer not to crate her when we are away as that might increase any psychological stress and I understand that dogs are pack animals and shouldn't be left alone too long. Again, I've worked with a veterinarian extensively on this, but I am hoping that maybe there is a diamond or two in the rough from unprofessional opinions and anecdotal evidence.

Thoughts?