Unfortunately, many parrot species are not compatible with each other, even if they are raised together from very young. It only takes a moment for a parrot to bite and if it is a biting a smaller bird, the result can be a serious injury.
Budgies are friendly and sociable bird, but they are also pushy and inquisitive. They can annoy larger parrots and might not realize they are in danger until it is too late.
Lovebirds are great little birds, but they are known to be rather bitey when they are displeased and their bite is bigger and stronger than a budgie's. As a baby, your lovie might be able to tolerate your budgie, but when it grows up, it could decide it has had enough. There is a real risk that your budgie could get hurt.
Definitely don't keep them in the same cage. And be very careful to always monitor their interactions so you can separate them if there are any signs of trouble brewing. You might not get much warning ... or any ... before something bad happens.