Embarrassed to be nude in front of husband

My husband and I just got married in March and of course we are all over one another during this honeymoon phase. He has asked me to come out of the shower naked and to bend over in front of him and let him go down on me from behind but my problem is I never, ever let him see my butt crack! Lol! It’s waaay darker than my skin, I’m an olive skinned Latina so that might be normal? He’s a white guy who has dated/been married to white women and I fear it will be a turn off. I HATE that it is dark, it looks SO dirty to me. He so badly wants to see all of me and does not care what it might look like but *I* care. I know he’s my husband and that it shouldn’t matter but I don’t know how to get over it and just let him see it. Anybody in the same boat? Suggestions please? Also could this be a hormonal thing? It used to be maybe just a shade darker than my skin color up until 8 yrs ago when I got pregnant from my ex husband. I’ve looked into skin lightening kits but none have many positive reviews and even if I went to a dermatologist i read the lightening isn’t permanent. I want to give in to all of his desires but I am so embarrassed. Please help!!!