You kinda have 3 choices, don't you:
1. carry on as you are (probably not viable long term)
2. jack it in with the current GF/BF and give it a go (might be fabulous, but is likely to lead to a suspicious relationship because of the way you got together)
3. Stop right now and not risk what you already have. (Boring but easy, or leads to long-term happiness if you and you current GF actually have something).
Only my opinion, nothing more. Not sure what I'd do, if I'm honest, since we all tend to love the excitement of a new relationship despite knowing that it NEVER stays like that forever...

