You might not feel so in love with your lovebird if he starts biting you. However, a lovebird will rarely nip for no reason. Once you figure out why he's biting, you can start to address the problem.
Some lovebirds will start to bite certain family members or guests out of jealousy. In the wild, these birds mate for life, so a pet will often become bonded to one human, usually the one that interacts with him most often. He then might bite anyone he sees as a threat to the relationship. If this is the case, you need to show him that interacting with others is enjoyable and that these people aren't a threat. Have him sit on a perch while other family members or visitors feed him treats and fuss over him. He'll soon learn to enjoy interacting with others.
Your lovebird can become territorial over his cage, and start biting if you encroach on his space. A lovebirds can become territorial over a nesting box; if he has one, remove it from his enclosure. A bird with this problem needs confident handling. Offer your finger for your pet to step on to. If he lunges for you, gently remove him from his cage wrapped in a cloth instead. Keep doing this every time you need to get in his cage and he'll eventually choose the easy option and step onto your finger. You can also try moving his cage and the toys inside it around, so he doesn't have one particular area he feels like he needs to defend.
A lovebird may bite because he's afraid. Fear can be cause by rough handling or nervousness. If your lovebird is fearful, try not to stress him out. Pick him up in a small towel when you need to remove him from his cage and don't handle him too much until he has become used to your presence. Don't let any children or people without experience handle him without proper supervision, as they might not realize they're being too rough. Be patient with him, and he'll slowly learn to trust you.
Other Reasons for Biting
Your lovebird might start to bite when he moves toward adulthood due to hormones and changing needs. This phase usually passes, and he may just need some extra space and for you to respect his boundaries. Lack of sleep can be another reason for biting. Make sure your bird is in bed by 7 or 8 p.m., as he needs enough rest to function properly. Some lovebirds bite to get their own way. If he seems to be biting to get what he wants, don't give him any attention -- or even react to the bite -- and make sure he doesn't get what he was after. Once he realizes his bites aren't getting the desired response, he'll soon get bored and give up.