It doesn't matter if it's for a LTR, a FWB relationship. Novelty is tied to attraction, so this question might be similar to "How to sustain attraction?", but I think it's just one aspect of attraction and that question has been answered a lot.

So, how do you keep being interesting, sexually if with a FWB, overall if it's for a LTR? It's even harder for the latter, since you spend a lot of time with the person, especially if you live together. What's the key? Is simply being exciting, having a thrilling life enough?

Reason for posting: I came out of a 6.5-year relationship a couple of months ago, we broke up because she got bored with me. She got interested in a guy that wasn't better looking, more confident or had a better personality than me, but he showed interest and was something new. But really, we had great communication and cleared it out, so the reason that we broke up wasn't the guy per se, but the fact that I had lost her interest. So I've been a little discouraged and have been wondering how I would keep it interesting with people, especially with people that I would see often.

But for this not to be too specific, just consider the above a small explanation, the question is what to do in general.