I think you should wear your ring as it is. Your partner bought it for you to wear and love. You can always add eternity rings later.
Unfortunately I cannot, my hand isn't suited for the ring he got me, it looks too snug when it fits correctly, so what was suggested is go up a half size and put a small band that's my correct size on top to hold it down. Otherwise it will fall off. We've unfortunately exchanged it 3 times. Obviously normal people would just swap the actual ring, but since he picked that specific design for me I want to make it work.