25M My boyfriend recently started inserting his penis into his anus. Are there any repercussions?

NSFW account and tag for obvious reasons.

My boyfriend has recently gotten into penetrating his own anus. I used to be fine with it but recently he’s mentioned doing it without a condom.

We both have no history of STIs and I test myself every once in a while even though we are monogamous, but is it possible that he might contract a disease?

We have only ever had anal sex occasionally and with condoms, but I always refused to touch him post sex because I deemed it unsanitary until he was done showering. Now he does the same thing to himself without a condom stating that he can’t contract his own diseases. Isn’t it unsanitary and absolutely **not** risk-free to do so?

We have started using condoms again because I’m afraid of contracting a disease from him until he gets tested again.

I apologize if this post seems ridiculous, but this is not something I’d go to the doctor for and I don’t really know where to ask. If this is not the place, feel free to redirect me elsewhere. Thank you.

…As for why he does it, I can’t say. I haven’t asked, and I don’t want to know. We encourage to express ourselves sexually and I don’t want to shame him for doing this. He’s always had a high libido but we have frequent sex, and says he couldn’t be happier with our sex life, so at least I’m not the reason he does it. At the end of the day, if it makes him happy and it isn’t detrimental to my health, then I’m happy for him too.