There is no safe sex, only safer sex, and nobody can decide for you where to draw your line when it comes to protecting yourself - it's personal to you.
I don't do unprotected oral, but it's 50/50 between the health risks and just not wanting some randoms bare cock dribbling in my mouth

. I do know quite a few women who have caught chlamydia and/or gonorrhoea, but that doesn't mean you will (or won't) and so much depends on how busy you are, your general health and dental hygiene and so on.
Have you discussed it with your GUM? They'll know the prevalence of infections in your area and can give you tailored advice which we can't here

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