I had my breast done 8 years ago, I had nothing, they had trouble fitting one of the implants because I was so small, that breast is somewhat hard still and the other drops over very far and moves a lot! My cleavage gap is just that a huge gap when I lay down, could send a picture privately but wondering if this is normal.
Smooth round implants can slide over time. Aging can also widen the chest width. Another surgery could correct your implants. You could consider a textured implant, which has the slight risk of ALCL but less lateral displacement over time. You also may be now able to have a larger implant if desired. The one implant may have bottomed out. The other option is securing the lateral and inferior fold with suture. You should see a board certified plastic surgeon or two for opinions.
Thank you for sharing your question. It sounds as if you have a couple of issues taking place, neither of which is "normal." Best to submit photographs or seek out in-person consultations for the appropriate diagnosis and treatment plan.
I agree with both colleagues. It is possible that each one of your beasts require different surgical strategy achieve a nice result.