Just out of interest, what are your thoughts on the chances of catching something with a straight female (as a straight male) when always using protection? I do really want to try it again, and I know I’m overthinking, but hearing people’s experiences of sleeping with hundreds of people with protection and never catching anything does make me feel reassured of how small the chances are.
I think the chances are slim to none. But I think that there are some matters which you can check which may help reinforce your feeling of control over the risk - which to my ear sounds like where your problem actually is.
1. Check the condoms you are using have a suitable kite mark. A lot of SPs will have them provided for them from clinics etc. There's no harm in asking an SP ahead of booking which brand she uses so you can check.
2. Practice putting your johnnie, nodder, sheath etc on yourself.
3. Ask about lube.
A properly fitted condom used correctly with a vagina that isn't like sandpaper will remove pretty much all risk of anything that can be prevented by wearing one.