I just wanted to respond to this as someone in a very similar position - I love the BDSM, my boyfriend does not.

You say, "She seemed into it in the heat of the moment but has never initiated this type of play since."

So if I understand this, you tied her up and she enjoyed it? That's awesome. I'm not surprised she hasn't initiated - she may have thought of it as a one-time event, or she may be too shy to talk about how much she enjoyed it, and what she would want to do the next time. I've had to learn how to talk about BDSM with my boyfriend because it's not the type of conversation he'd ever had before.

Ask her - and also persuade her with lots of hot vanilla sex just the way she likes it - that just as you love to please her, she (presumably and hopefully) loves to please you, and it would please you greatly to do ____ in the safest and most respectful of ways. Repeat at intervals, interspersed with great sex. Accept that you may not get your more out-there desires met with her as one of the compromises that enter all relationships. Take things slowly - a little self-torment never hurts, and if she's the one for you you'll have the rest of your life to work on this.