Sometimes, love bites.

Most days, love chugs merrily along with hardly a hiccup. Some days, it seems to shudder and fall apart over some minor mishap, real or imagined. Sometimes, it falls apart because of the pets.

Pets enrich our lives in lots of ways, but it’s not all nickering fillies, wet noses and kitten purrs. Couples can disagree over the breed of dog to get, the hair length of the cat – even over whether to get a pet at all.

As a veterinarian, I’m slightly biased. I pretty much depend on all of you thinking “This dog is WONDERFUL! I would like eight more, please, and throw in a litter of kittens” all the time. For my chosen profession, it’s a case of the more (kittens hanging out by the hearth and puppies playing by the porch) the merrier. But I understand and sympathize with pet owners for the sometimes overwhelming responsibilities of pet ownership. And those responsibilities can tax a couple, just as they can tax one person.

In many cases, one member of the couple may already have a pet as they enter into a relationship with the soon-to-be-other half. In those early, heady days of love, where even the attributes of a serial-killer are forgiven by love-blindness, the idea of your loved one’s pet may not seem so bad – and you don’t have to live with the pet, yet, so you just get to pat-pat on the head, skrittchy-skrittchy under the chin and Bob’s your uncle. Love and bliss and pets.

But sometimes all the ingredients don’t mix well – you may be an ailurophile with 14 cats in your possession who starts to date someone who owns three greyhounds that love to chase cavorting wee beasties. You can perhaps chart the course of that ship. Or maybe you possess the world’s nicest dog – until a chubby infant hand wants to see what he’s chewing on. And let’s say you’re dating a dashing divorcee who is mother to three divas-in-training. That one’s a potential powder keg, and no diva looks good with stiches.

In some cases, you may have one member of the pair who loves pets and one who is neutral, or even anti-pet. Hopefully this alignment of pet feelings is rare, but when it happens, it can be one more cause of discord and disagreement in a relationship, even a deal-breaker. This is a central theme in the Animal Planet show “It’s Me or the Dog” and it can make or break a relationship in much the same way that other stressors can. Couples have broken up over less: dirty dishes, not filling up the gas tank that one last time, messy laundry habits.

The permutations are endless. Just as with hobbies, religious beliefs, food preferences and levels of gluten tolerance, feelings for pets and their trappings can unite or divide a couple. For some, love of pets and trips to the dog park are the nidus of a lasting relationship that can lead to marriage and the next generation of humanity. For others, stepping in (another) cold pile of cat barf at 2 a.m. is the last straw and you find yourself scanning the personals, looking for Mr. or Ms. Pet-Free-Home. It’s like two poles of a magnet – line them up right, and you have a permanent attraction that’s strong, invisible and lasting. But get them misaligned and *sproing,* you are cuddled up with Mr. Whiskers…alone.

A common flash point that can trigger many a domestic squabble is…stuff. Things. As in “this is why we can’t have nice things.” When you are a twenty-something living on a ‘couch’ fashioned out of pillows and milk crates, eating mac-and-cheese out of a Frisbee (true story), you may not give a tinker’s damn about a few scratches here and there, a little furball dotting the landscape.

But when you turn into an adult and perhaps hit your stride in your thirties, you start to give a crap about your stuff. Animals don’t; they don’t care if your couch cost $1500 or you scavenged it from the loading dock at the Pick-n-Save. They can trash that $1500 couch with the same high level of efficiency as the $15 one. As you put aside childish things, the pets may chew or pee on them. A pet who fit right in when you both were impoverished bohemians may no longer be welcome in a Pottery Barn home.

Sometimes one half of a couple is far more tolerant of housetraining issues – medically or behaviorally based - than the other. One doesn’t consider it a problem to pick up poop from a dog who just came in from the back yard, or to wash bedding after a cat with struvite crystals pees on the comforter. The other minds it a lot.

I sometimes see the manifestations of this phenomenon in the exam room. Couples often disagree about the lengths to which they can go for a pet, medically or financially. The pet and I are often lodged in the middle as the two halves of the couple duke it out and try to come to some middle ground. Sometimes they can do it, sometimes not. The husband may love the cat and want to go to the ends of the earth for ‘his’ cat, while the wife clearly is thinking “free kitten – lots more at the shelter.” Or the wife opts for the MRI and spinal surgery for the dog, while the hubby is doing the math on a new dog in his head, not wanting to shell out the shekels for ‘her’ dog. Veterinarians have to help guide them through this mine-strewn landscape, while keeping the needs of the patient in sight the whole time.

A veterinarian I know is married to a man who, when they met, had horses and a dog that lived in his barn. Before he met her, he had never lived with pets inside the house. She has several cats and an indoor dog to boot. While he is usually vastly entertained by the cats, their indoor status and occasional transgressions against the furniture or carpet comes up once in a while in the midst of stress or disagreements about other things. The cats are never the starting point of an argument, but their follies are often brought up and tossed into the general fray when something else goes awry.

My own experience with pets and love has gone well, with the odd, and expected, hiccup. Our dog Rocco was my wife’s when we met. Rocco is the canine intellectual equivalent of a brick of Velveeta, and has a nasty habit of barking like all the hounds of Hell turned up to eleven whenever someone has the audacity to ring the doorbell. Every other non-ringing moment of the day, he is a sweet, loving, and mild-mannered (albeit daft) pooch who lets the two tots in the house crawl all over him and use his ears to perform puppet shows. But hit that shiny button beside the door and he channels his inner Cerberus and lets loose, which always sets my nerves on edge, occasionally wakes a sleeping baby, and probably causes permanent soul damage. I can’t tell you how many times my wife and I have had tense words over his doorbell habit, and there’s nothing to be done about it. So we live in an uneasy peace until the next time the doorbell rings. We rarely order delivery.

I try to keep it in perspective. For every Cerberus moment, there’s scores more of happy walks to the lake at dusk, quiet nights by the fire, or aural puppet shows accompanied by squeals of babytot delight. When I look at him as if to say “You OK with this, buddy?” he gets a look in his eye that says “I’m cool – they can do it. No problem.”

I don’t hold the secret, or have any of the answers. As a vet, I’m not qualified to give relationship advice – just advice on maybe how to keep the cat from barfing at 2 a.m. So I can’t really help the lovelorn and pet-torn, but I do think this phenomenon warrants some scrutiny, and perhaps the input of a pundit or two, someone with a PhD in either relationships or magnetometry.

The pluses of pet ownership usually outweigh the minuses – that’s why so many of us do it, and keep doing it. But get a pet or 14 squeezed in between your magnets, and you all may be in for a rough ride. If the problems become serious enough that either the pet’s existence in the home or the relationship itself is in danger, then you may need to get professional help from a counselor and/or pet trainer/behaviorist. If the problems seem to be of the more day-to-day sort, then a sense of humor and a focus on all the times things do go smoothly will help get you all through the tough times.