The Last Few Times I Have Had Sex With My

The last few times I have had sex with my boyfriend his sperm smells like fish and I almost always suffer from a UTI. At first I thought it was because he was a fisherman and eats a lot of fish...but now I know better. I am concerned we are not compatible sexually as due the possibility of his sperm and my uterus appears to have become acidic and not balanced on a PH level. Am I wrong, can this be fixed....why is this happening?
-Renee