You can certainly have more than one spirit guide while being in your spiritual path. You don't have to stick around with a single spirit guide during you spiritual path and journey. I myself had a lot of spirit guides, not all of them were good or qualified, some of them were even a bit 'nasty'.
Spirit guides are all around, thus you will have more than one in your spiritual path if you choose to. It's only up to you to decide if you're ready to be guided by more than one spirit guide in your spiritual path / journey.
For an instance, if you have more than only one teacher at school, you can have more than a single spirit guide :)
Oh, and to make it clear, even if the spirit guides do not tend to leave, you can choose if to keep being guided by them or not.
If you let one of the guides go, you can obviously be guided by another one.