I don't dance bachata, just not my thing, and yes, it can be marketed as being quite sexy, but...
I do dance salsa, tango & lindy hop, and one thing generally in common is that dance classes are very respectful and it's totally normal and not at all an issue to go individually, rotate partners to dance with everyone at the class who's dancing the opposite role (lead/follow), and there's nothing in it - we're all just there to learn/improve our dancing and enjoy the social dance and the music. That applies for every style of dance I've ever tried, including the whole 2 sensual bachata classes.
Equally at social dances, we ask/are asked by most people to dance, so we can get to enjoy the dancing and the music, which is after all the point.
But... If you'd be up for ballroom, why not join him at salsa/bachata? Salsa is much less "sexy" than sensual bachata, and everyone at any class I've ever been to is very casually dressed. Maybe a bit more dressy at socials.
Plus... It's generally accepted that at beginner levels it's easier to learn to follow than to lead, so you'd likely get better quicker than him if that worries you. Anyone can dance either role, of course, but most women do follow, at least to start.
And it's fine at social dances to sit around the edges and listen to the music and watch the dancers - most people don't dance every song, it's too tiring! - so you could join him if you wanted, and it would likely be less intimidating than you think.
It's a lovely hobby, and can be even nicer to share with your partner - why not just try a few salsa classes and see how you feel about it?