Why have I started getting tonsillitis after giving oral sex?

[Emjay222]

I have had the same boyfriend for 3 years and have been performing oral sex on him for most of that time (he loves it) and haven't had issues until the last 6 months. I've gotten tonsillitis 3 times this year, once in January, again in late April, and now again at the end of May. Two out of these three times have happened the day after performing oral sex (January and May occurrences). He normally finishes in my mouth and I swallow it.

Again, I haven't had any issues until recently and I've never gotten tonsillitis in my life until this year. I'm a healthy 25 yo female and was checked for STDs when he and I became sexually active, all tests came back negative.

I'm in the process of making an appointment with my GP to fix this most recent infection but I don't understand why this keeps happening and I'm tired of constantly having to take antibiotics. For the occurrence in April, I had to take two rounds of antibiotics as the first didn't work, along with prednazone to take down swelling since it had gotten so bad.

I think my next step is to get my tonsils removed but I really don't want to (a little scared tbh) and I want to understand why these flare ups have happened all of a sudden since we've been successfully performing this action for so long.

Also, the first time I had tonsillitis, I thought it was because my bf had inserted a finger into my anus during sex (something he recently started doing) and later put the same finger in my mouth. I thought the tonsillitis came from bacteria on his finger. This time (third occurrence) he used his tongue on my anus during sex (also newer, but he did that once when we first started dating and I had no issues) and we kissed afterward. I'm wondering if that's why I have it now? Although my bf is totally fine so why wouldn't he have tonsillitis if it was his tongue?

I'm basically looking for answers on what the cause of my recurring tonsillitis might be. I don't want to stop oral sex since he likes it so much but I'm looking at common experiences surrounding my flare ups and that seems to be a big one. Could it be something in his semen? Should I get retested for STDs? Should I just get them removed and hope that works?