Can’t you compromise? If she agrees to make more of an effort for you two to get some alone time, you’ll sext with her as often as she wants. I’m sure this isn’t because she doesn’t want to have sex, but rather she’s trying to have SOMETHING since you two aren’t seeing each other as much. This seems to be her way of trying to still keep things going, still staying in touch with you when actually being with you isn’t an option.
When you’re in tough situations like that with parental restrictions, you have to try to make the best of it. It’s not easy being a teenager in a sexual relationship ‘cause parents are a constant twat block, but you have to work around it!
Express to her that you miss being alone together, you miss being with her like that, you miss being able to actually touch her instead of talking about touching her. You miss HER. Don’t make it all about sex, because you know it’s not. It’s about having that physical, tangible intimacy, that satisfaction you get being able to hold her. Sexting can only do so much to hold off your need for that. Explain this to her! Then give her what she wants and just ask her to try to make an effort for you as well (you said you didn’t mind sexting, right?).
She wants to stay in touch with you by having “virtual” sex and you’re frustrated because you want more. Well, sometimes you can’t have more. So try to understand where she’s coming from instead of just saying “why talk about it when we should be finding ways to do it!”. She’s just trying to be with you however she can and your response sounds a little bratty… (No judgment! I get your frustration, but you need to be realistic about your situation.)
Use all and any opportunities you can get for alone time. If the parents are out, in the afternoon when they’re at work, sneak in at night for an “unauthorized” sleepover (and out early in the morning), use a car, etc. I know I probably shouldn’t suggest going against the rules and restrictions your parents/her parents have in place, but…you just want to be with your girl, you’re not hurting anyone, and sneaking around a little bit isn’t the worst thing in the world. Just don’t let it get in the way of your regular responsibilities (school, work, studying, whatever else you have going on).
COMPROMISE. You’re not going to get everything you want at this stage of your life so just make do with what you can and don’t take anything for granted. You’ll get more freedom and independence when you’re older, but for now, make do, and enjoy whatever time you have together.