So, John recently began a relationship with Jane, who he has known for all of 3 weeks. He spent a 3 day weekend with her last week and at that time became fluid-bonded with her, which he neglected to tell me before we had sex after his weekend with Jane.
I became upset with him and concerned. I don't believe that 3 weeks is a long enough period of time for one to come to trust a person enough to put their health and lives in their hands (i.e. not use condoms with her). I believe that trust like that develops over time - a whole lot more time than 3 weeks. I tell him that he barely knows her, that he doesn't know her well enough to put his health and life in her hands (but that's up to him whether he decides to take that risk or not), as well as my health and life in her hands (I don't want to take that risk as I have only met her once and not spent any considerable amount of time with her at that meeting), i.e. he doesn't know that she isn't having unprotected sex with other people without his knowledge. He takes offense to this because "she's wonderful," "she's amazing," and he knows she wouldn't lie to him about or keep from him the fact that she's sleeping with other people (without his knowledge) without condoms.
Nonetheless, I tell him that I am not comfortable with having unprotected sex with him for as long as he is having unprotected sex with Jane. Now, perhaps, in 6 months to a year, I might decide I no longer wish to use condoms with him - so long as everyone involved tests STI-free.
It's been a week or so since all of this occurred and just today I find out that Jane is also having unprotected sex with another partner besides my partner, John. I know this other person as well as I know Jane, which is to say not at all. John knows him as well as he knows Jane, which amounts to all of 3 weeks. BUT he insists that he trusts that this other partner, Tom, both has no STIs and isn't having unprotected sex with anyone else but Jane. Now I tell him I'm even more uncomfortable with the entire situation and the reinstatement of condoms into John and I's relationship is paramount.
Now he is telling me that my concerns are nothing more than jealousy, that there is little risk of STIs being passed around between the four of us. He says that since he is male and having sex with Jane, who is female, his risk of contracting an STI from her and passing it on to me is very unlikely. He's also informed me that he has given and received oral sex without protection with numerous women over the time we have been together and hasn't contracted an STI during that time, therefore apparently bolstering his view that him being male presents a very low risk of him contracting an STI from Jane because she is female.
SO, I come to you for advice. Am I being unreasonable? What information about STIs can I share with him to increase, what I believe, is limited (or maybe selective) knowledge about STIs?
I apologize if this is confusing and if anyone needs clarification on anything above, please let me know. Thank you in advance.
ETA: I have an appointment with my primary care physician on April 1st for my annual check-up/pap smear/the works, which will include STI testing. I've invited John to come with me so that he can share his views and ideas with my PCP and see what she has to say about them, as well as ask any and all questions he has.
Thank you all so much for your responses, your support, and your sharing of information/links. I really appreciate it and will be giving this situation considerable thought.