Boyfriend rarely brushes his teeth

Hi all,

I’d really love some advice:

I have been with my bf (now fiancé) for around 3 years and we have lived together for a year. In this time I’ve noticed that he rarely brushes his teeth- never in the morning, so only once at night, if he even does that.

I’ve asked him why but can’t get a straight answer. I’ve told him it disgusts me and gives me the ick but no change. He is adamant his teeth are fine with only one brush as the dentist didn’t pull him up on anything at the latest checkup (but he’s had plenty of teeth out/ infected in the past and doesn’t seem to connect the dots)

Please can someone advise me, how do I get him to change 😭