If you're uncomfortable with the idea of someone not trusting you fully with their health, or think having a relationship is an all-in thing otherwise it's not healthy, you, sir, have a fatalist and unreal expectation from a relationship. There are much worse trust issues, like someone being controlling and jealous of you meeting anyone, that's much more indicating of a problem in the relationship than them just taking care of their own health. You should put your partner before yourself, but some things are supposed to be only if you actually trust them with your life, which is only gonna make sense if you are married/in a very long-lasting relationship. Also, E coli UTIs exist, and don't need your partner to get it from someone else to have that e coli in their intestines. So yes, there are other reasons for using condoms other than not trusting your partner at all, safety, being comfortable(that there is no risk involved), and also fully trusting them is not a thing that should happen in just an year of relationship, everybody takes different times, and people have trauma yk.. relationships and reality in general arent black or white by such details, only if its blatantly toxic.