Speaking as someone who is reluctant to walk around in front ofmy partner with no make up on I had similar fears to yours. But seriously, trust me, they are ridiculous,you are seriously underestimating him and my boyfriend was my rock throughout. Giving birth is hard but also magical and without being gushy my boyfriend is like my best mate- I don't understand why you feel that his feelings are so shallow towards you that you delivering his first child into the world will put him off you?!! And why you wouldn't want to share one of the most important moments of your life together?
Think about it logically- it's bizarre how you feel lol. In the weeks after when you are sore, bleeding like mad etc it will make much more sense to your partner as they will appreciate the hard work you put in to deliver your child and will not just think you are giving him the brush off as they will understand what you have gone through. They will also have new respect for you. As someone else brilliantly said, you sometimes need someone to fight your corner as NHS services are pushed and you are not at your most coherent and mobile to go and nag for things if they are not being done. Lets face it- no one's lady bits are gorgeous anyway and your partner was interested enough before!
As an aside- one of my biggest fears was going to the toilet (you know what I mean lol). My midwife was fab at getting my bf to run to the vending machine etc to get 'water', 'sweets' etc whenever she sensed I was feeling embarrassed- they are used to it. It was all in my head though as it happened.
Let him be there- he sounds a lovely bloke and trust me anyone could wander in and have a nosey by the time your in the full throws (sp?) and you wouldn't care. Believe me, it will not put him off sex- by the time he's waited for you to heal/stop bleeding he'll have forgotten any issues you think he might have.
Good luck xxx