There is nothing inherently wrong with this situation, and it doesn't have to mean that the group of PCs are bound to split at some point because of the clashing alignments. However, allowing such a group of PCs means there are responsibilities on the GM and each of you as players to make this work, and all of the players at the table need to be comfortable with this style of play. From your question it sounds like you might not be, but that doesn't necessarily mean there is a big problem here.
Trust and work with your GM
You don't mention how experienced your GM is. They may know exactly what they are doing and you have nothing to worry about. It sounds like your GM is comfortable with the idea of having a group of PCs with sometimes conflicting motives. The mix of alignments that make up the party pretty much guarantee that inter-PC conflicts are going to happen, and in order for these to mean anything in practice, the GM has to use and play on them to some extent or another.
The responsibilities of the players in these situations
When inter-PC conflict such as this comes up, it is everyones responsibilities to try to ensure there is good reason for the group of PCs to continue working together. So while the GM is playing on the temptations of the PCs with clashing alignments, it is everyone in the groups responsibility to work with whatever comes out of any resulting conflict in a constructive way, creating reasons for the group to stay together.
Out of character conversations can be really important
With this kind of thing it can be really important that everyone is on board with whatever is happening to the PCs. With a group of players who are used to playing together this tends to happen more naturally, as they are used to each others play styles and can often predict how each other are going to react. With a new group of players this is more difficult, and can necessitate a lot more out of character conversation to work through potentially tricky situations in such a way as to ensure that all players are comfortable with the way character development and the story are heading.
It might be worth having a conversation to make sure all players are on board with this type of play
From your description of the situation it sounds like the GM might have missed an important step during the initial sessions in the game. As I've already mentioned, this type of mix of PCs is almost guaranteed to lead to a certain style of campaign if the PCs' alignments are going to mean anything in play, and some players simply don't enjoy that style. What should have happened is that a conversation about this was had to make sure everyone was happy with the idea. If this didn't happen, there is nothing wrong with pausing the game to do so now, as it is entirely possible for (often quite subtle) changes to be made so that the style of gameplay is enjoyed by everyone at the table.