People change after marriage (Photo: Thinkstock | The Bump)

1. The change is unavoidable -- and often unspeakable.
"If someone tells you that their marriage didn't change, they're not being honest with you. When you go from just you and your spouse to you, your spouse and a baby, things will change. Change isn't a bad thing -- at least not always." -- jiffymama616*

Sound familiar? Remember when you thought your baby was going to fit neatly into your current life? Nope, not happening. Once you have a baby, you become painfully aware that your life now revolves around this little helpless being who needs you -- and who despite having a pretty simple existence (eating, sleeping, pooping), needs round-the-clock care and undivided attention. Consider your world officially rocked -- your relationship included.

2. You might hate your partner a little bit.
"I was so hormonal and crazy from breastfeeding, and my husband had a hard time because he didn't know how to help." -- busymama113

Maybe hate is a strong word, but you might find yourself snapping at your partner a whole lot more than you used to. You might resent him a little for going to work while you're home on leave, you might despise the way he fastens a diaper or mixes a bottle or washes the whites. But remember: This does not mean you're headed for divorce. Some people call those early mood swings -- likely a result of hormonal changes and sleep deprivation -- the baby blues." And they're normal, as long as they don't escalate into postpartum depression. Your hormones will eventually balance out -- but you've also got to make up your mind to snap out of your bad mood.

3. You don't nurture your relationship the way you know you should.
"We didn't really talk about how things were going to change once we had a baby. Sure, we talked about diapers and day care and discipline and stuff like that. My husband travels for a living, so when he would come home, he would want 100 percent of my attention, but he had to wait or try to talk over a crying baby and, now, chatty toddler. That was hard for both of us. Mostly our challenges came from not having the time and attention for each other like we did before." -- lilmama514