Hi Red2Blue, welcome aboard Filipina Roses

I'd strongly advise NOT to engage any agency at all from Philippines in connection with ANY visa for UK

Since you are already married you're not eligible for any visa involving Fiance or Spouse.
For unmarried partner visa you must have lived together for minimum 2 years in a relationship akin to marriage.

It seems only Visit Visa is possible.
Check out the UKVI webpage and see how you might apply.
You'll need to show reasons to return to Philippines that are stronger than reasons to stay in UK

There are any posts here in the forum to guide you on that.
Good luck. Follow the UKVI webpages, follow the visit visa postings here in the forum, then ask any specific questions you have. You'll get honest useful answers.

God Bless