I’m gonna be ridiculous. Health anxiety about STDS!!

So I’ve been with my partner almost 3 years. We didn’t get tested after we got together. I was tested and clean but my partner was in a long term relationship prior and used protection with any one night stands so the chances of contracting an std is very slim. However I feel obsessed over it. I’m scared because I’m bleeding after sex (only since giving birth recently) and experiencing pain during sex which again is since child birth. Smear test came back low grade cells and they’ve taken a biopsy. Mt partner is so uneducated and says well if you’ve got any form of STI then I’ll be questioning you because I didn’t have one because I had no signs of it (he thinks he’d get symptoms 🤷‍♀️) again I know the chances are slim but having symptoms is scaring me but I know deep down it’s probably down to something else. Surely if it was an std it would’ve shown in pregnancy/ affected fertility/ hurt my baby when he was born 4 months ago? Please tell me I’m being silly. I can’t help but be super anxious. I’m too scared to get tested incase he accuses me of doing something I haven’t and he walks away. I guess I’m just asking for some reassurance. Thank you for reading my rant!