Couples don't always have to address each other on first name basis or stick to calling each other one pet name. There are many other sweet names to call your significant other so you really don't have to run out of ideas.
Holly Riordan of Binoni lists a few awesome names you can call your significant other:
Baby: You either love this nickname or hate it. Of course, you're not restricted to using the word by itself. You can always add on to it if you feel the need. There are tons of pet names for your significant other that begin with ‘baby.' There’s 'baby doll,' 'baby face,' and even 'baby boy.' Stick to whatever sounds best to you.
Darling: This is a cute and simple way to address your partner. It's similar to the name 'dear,' because it suggests that you really care about the other person. It's perfect for both a serious relationship and one that's just starting, because it's something that you could also call your close friends.
Honey: Honey is sweet, which is why you should use this when talking to your super sweet partner. You could also call them 'honey bun' when you want a different sounding nickname. Either way, they'll love hearing your voice say it.
Pumpkin: There are dozens of nicknames that involve food, so this is not your only option. You could also use the name 'pudding,' 'muffin,' or even 'cookie.' The list goes on and on. Just open up your fridge to think of some new ideas.
Sweetie: This nickname is self-explanatory. Use it on your partner if you believe that they're the embodiment of sweetness. They're sure to return the favor by calling you a name that's just as flattering.
Boo: This one has become pretty popular. If you want something simple and séxy, this is your best choice. It sounds casual, but it also suggests that you're together for the long haul.
Angel: If you think that your partner is perfect in every way, then this nickname should fit them perfectly. They can do no wrong, so to you, they're like a little angel.
Handsome: Everybody loves to be reminded of how attractive they are. If you don’t like the word 'handsome,' then you can say ‘gorgeous’ or ‘séxy.’ No matter what, it'll show your partner that you're still swooning over their looks.
Cutie Pie: Sometimes, it's hard to handle the adorableness of your partner. During those times, you can break out this nickname. You might not want to use it in front of his (or her) friends and embarrass them, but you can use it all you want in private.
Love: If your partner is the love of your life, then you might as well address them as such. You could also get more cutesy by calling them 'lover boy,' or 'love muffin.’ Anything's a possibility.
Pookie: This one is a bit corny, but sometimes that's exactly what you need. If you want to go down that road, you could also say, 'snuggle bunny,' or 'stud muffin.'