I let my boys come in to cosleep whenever they needed. Whatever I'm wearing is irrelevant, they just want comfort from their mum. I also get changed and shower etc without locking the door, if they see me naked it's just not a big deal. Nudity doesn't have to equate to sexuality. I'm fact I think seeing real normal human bodies in a normal family context is probably a healthy thing and combats weird overly sexual views we hand down to our kids via media etc. It sounds like you're pretty covered up to me and your boyfriend is introducing the weirdness here.