What is something he has as a part of his life that makes you feel inadequate due to lack of knowledge and experience? (You do not have to answer that here, just to yourself...).
With my husband it was his musical abilities and talent. I am sooo non musically inclined that it made me feel completely foolish and inadequate. I have had him explain and try to teach me just basics but that did not work to make me more comfortable either. Then he explained each of his guitars, the features, why they were unique and the ones he wanted...I found my niche in his interest. I have a phenominal gift for facts and research. I can now find the guitars he may be interested in for him, scan out the ones he would not be interested in and he can then pick and choose the ones he wants to actually purchase without the hassle of weeding the others out. No--I still can't play them or want to, but I do enjoy listening to him play and finding new treasures for him.
This can be applied to your sexual life as well. Your boyfriend may feel like he will never 'catch up' or be equal to you in experience. However, if the two of you could find some common ground--an area you both could be interested in exploring together and learning about it would do wonders for his sense of equality and security. I was a late developer sexually due to having a painful disease when I was younger. I had endometreosis and anything close to orgasms were very painful for hours afterwards. It wasn't until AFTER my hysterectomy at 22 that I figured out what all the fuss was about--and I haven't looked back!
That set me way behind experience-wise and I have felt pretty embarrassed and inadequate about that until my husband and I really found our enjoyment of toys together. We usually only use them together, we masturbate together and plan scenarios and fantasies for future fun. (Some of them for fun at the time only--but the closeness we have developed through everything has become amazing.) We have been through some very rocky and painful things over the last 17 years, but keep working together to change for the better (he has been sober now for 4 months!) and still find new areas that are still within our personal boundaries to explore.