We'll Always Have Parasites

My boyfriend of two months is a gem, but his house is a horror. The fridge and bathroom are disgusting, and the whole place is seriously messy. There's this eerie feeling that the house was formerly homey, like nothing has changed since his wife left him three years ago -- down to the box of sanitary pads in the bathroom cupboard and the very wife-ish folksy kitchen art everywhere. I wonder if the state of things reflects some inner devastation he's feeling post-divorce. He takes pride in his home's exterior, meticulously maintaining his lawn, and I don't think he's trying to impress the neighbors (not a pretentious bone in his body). He hadn't changed his sheets in our two months together, so I removed the pillowcases and dropped them on the floor as a hint. He didn't get it. It seems too early in the relationship to say anything. Still, I don't feel I should have to keep faking that I'm comfy in his home and in his bed on sheets that feel like they haven't been washed since the 1980s. --Yuck

A woman can leave a man, but apparently, cows grazing on a field of gingham and "Rooster Crossing" signs are forever. And of course, nothing says a man's open to a relationship like his ex-wife's 3-year-old box of Kotex. 
Welcome to the Museum of the Ex-Wife. At least, that's how you're seeing it, and that's understandable. In trying to make sense of things, people have a tendency to look for some underlying deep meaning. And, sure, maybe the biohazards and lingering Kountry Kitchen Kwaintness are reflective of some inner darkness on his part (depression, inability to cope with his loss and move on). Or...maybe it was his job to care for the outside of the house and hers to care for the inside, and after she left, he never thought to fill in the blanks on the chore wheel. Before long, the place became Home Sweet Bacteria Rodeo.
If you don't see other signs suggesting he's depressed or troubled, he's probably just mess-blind. It's hard for those who practice what would be considered ordinary tidiness and house hygiene to understand, but for some, all the chaos and grunge just blends into a big, benign whatever. The basic rule of this sort of laissez-faire housekeeping: If the crud isn't so big and scary that it's grabbing your ankle as you're en route to the toilet, why get your last pair of clean underwear into a wad? 
It is cute that you thought dropping stuff on the floor -- the floor of a man who basically lives in a two-bedroom landfill -- would have an impact on his housekeeping standards. You should actually consider it a bit troubling that he apparently made no attempt to tidy up for you. Even the most squalor-inured tend to look at their living situation through new (and horrified) eyes when a new romantic partner is coming over and try to do something -- get a backhoe in there, burn the bedding, crash a Febreze truck into the living room. 
I'm not suggesting you go all Joan Crawford on the man ("NO. MORE. WIRE. HANGERS!"), but you can't let him think it's no big deal for you to get in bed onto sheets that feel like they haven't been washed since the Reagan administration. (If you put out a message that anything goes for you, whether in the housekeeping department or any other, very likely, anything will.) Don't be pulling on any rubber gloves, either. (Start cleaning up after him and you'll keep cleaning up after him.) Instead, say something gentle but direct like "I think you're a great guy, but I really need you to clean your place so I feel comfortable there." There is a chance that he'll break up with you over this. But, what kind of man kicks the girl out of bed and keeps the cracker crumbs?
Instead of trying to get him to clean up his whole act at once, take things step by grody step. Whatever effort he makes, keep letting him know you appreciate it. If the house isn't getting to a civilized level of clean, gently suggest that it needs a woman's touch -- a cleaning woman's: "Ever thought of getting a maid once a month?" Finally, address the ex-wife's leftovers by joking that some of the decor doesn't quite seem a reflection of him. In fact, you're particularly confused by the box in the bathroom cabinet, but you'd like to be supportive: "A man's first period is a very special time, and there's no reason to feel ashamed about the changes in your body, which should soon have you turning cartwheels in a flowing white skirt."