Emotional Freedom Techniques can and will help you.
You don't need to become an extroverted celebrity but if you feel anxiour or afraid of getting undressed in front of anybody especially your significant other EFT can help you. You can start as easily as:
Even though I feel anxious about getting undressed when X is in the same room as me. I'm choosing to accept my and myself just the way I am.
Even though I hate getting changed in a public changing room. It makes me feel really uncomfortable. I'm willing for this to change.
Being relaxed in your own skin is very attractive and sexy regardless of your appearance. Confidence is always attractive.
Even though I do not feel confident naked. I deeply and completely accept myself.