You seem to have taken responsibilty - you apparently "dropped the ball" or whatever phrase you used .... He could've spoken to you about it if he felt you weren't warm/affectionate/positive/enthusiastic/affectio giving enough.
That's what a decent person would do; not look up and message prostitutes.
You're being had.
You're actually having yourself.
I knew it would be "but I haven't been ABC and ...."
He could discuss it with you, if discussing it with you led to no consistent change, he could separate.
There is no excuse/opening to contacting sex workers.
I also have severe doubts about the hair loss medication. So one person was suidcidal.on them, where does feeling suicidal and looking up and contacting prostitutes cross over? Usually suicidal and depressed people have no interest in sex.
Likewise a poster on here is on the medication and says that's not it.
As I said, you're being had/having yourself.
First it was curiousity to see what services they offer .... Everyone knows and why would you need to check if you don't plan to.use them? Then loneliness - except you two were in contact regularly and he had the opportunity to socialise with his brother that he turned down. Now it's your inattention/lack of enthusiasm/lack of affection (which he couldn't talk to you about, instead his solution was to message prostitutes - riiiight) and then the bizarre medication side effects claim.
Stop taking responsibility for this.
As for the "transparency" ..... You should never ever have to be your partner's bank manager, nanny, supervisor, patrol officer, mammy, moral guardian .... Checking what they're doing and spending because they contacted sex workers, that's completely fucked up.n