Hi, thank you for your question. Just a bit more information required to fully assist you:
-Are you in England or Wales?
-How long have you been separated for?
-Will your husband admit adultery?
Thanks for confirming. You are able to apply either under the fact of unreasonable behaviour - and rely on the new relationship as unreasonable behaviour, for which you do not need his consent, or you can apply under the fact of adultery, but this needs to be admitted by him.
I hope this assists you. If you found this information helpful please provide a positive rating using the stars at the top of this page. I will not be credited for your question without a positive rating. Thank you