© Dmitrii Kotin Tired parents

New parents often underestimate just what midnight feedings, teething, the Terrible Twos, and teenage years will do to their marriage. "Couples know having kids will change their marriages and their lives, but they aren't really able to appreciate how much it will change and in what ways until the baby comes along," says Andrea Ramsay Speers, psychotherapist and parenting coach. And while much, if not most, of the changes are oh-so-good, here are five you need to know about now so they don't throw you off down the road.

1. Attraction to your significant other may seem like an afterthought, leading to little or nosex life.

"Many couples find a decrease in frequency and a decrease in their desire due to so many obligations competing for their attention," says Speers, who's quick to point out that the difference between roommates and spouses is often what they do between the sheets. "It's important to keep this part of your relationship alive," she says, even if sex is the last thing on your mind.

2. Non-sexual intimacy — think: snuggling and holding hands — may slow.

While you used to while away an evening cuddled on the couch, now all of your "physical loving goes to the child," says Karen Ruskin, licensed marriage and family therapist. "If you are not mindful of this and take action to be physical with your mate, [a lack of non-sexual intimacy] can go on until the couple becomes disconnected and the kids are much older, if not forever."

3. You'll be tired. Like, all the time.

And that can translate into bickering and other bad behaviors with your spouse. "It's no secret that babies impact your sleep, but very few people are prepared for just how tired they're going to be and for how long," says Speers. "Fatigue impacts daytime functioning, mood, ability to cope with stress and change, and makes us much more likely to be short and ill-tempered with our spouses, which doesn't exactly help the marriage. "

4. You'll see just how your spouse deals with stress — and you may not like it. "Some couples can get along just fine until they become parents," says Speers, "and then, all of the differences between them and the expectations they brought with them to the marriage suddenly become apparent." Being a parent means being on-call every hour of every day, "and it can be quite thankless," Speers says. "It's easy to turn that frustration or feeling of inadequacy onto their partners, and take out their negative feelings on the one person who's in it with them."

5. You'll see your mate in different ways.

When you see him swaddle your newborn or push your toddler off on her first three-wheeler, it'll be through rose-colored glasses. But "once you see your mate doing things that annoy you because his or her parenting style is different from yours, you may find yourself annoyed at your mate and not enjoying who they are as a person," says Ruskin.