Questions about my 15 year old bf?!?

Okay, so I have a few genral questions about my "boyfriend", and I think these are questions that boys should answer. I've been with my boyfriend for 2 years, well we go out over the summer because that when we see eachother. He doesn't know my native language, but I know his well enough. We sometimes tal on via skype and he asks me to strip, I really want to say no, as a matter of fact I did once, but it was a while ago and I don't want to say it agian, because I really love him, we knew that when we first saw eachother. My question is how can I get my boyfriend satisfied without taking off my cloths or having ? Because I know he's a little dirty, we kiss all the time. And if we see other people over the summer an. He goes out with realy attractive girls is that going to affect o realationship? And any tips on how to get my boyfriend to love me more an for us to get to know eachother better? Thanks a bunch!