Does this count as relapse?

Hey guys. I started nofap about 20 days ago. I didn't have any trouble staying on no-PMO since I have very low libido to start with, and my boyfriend is on a trip abroad.
But yesterday he called me and said he wanted to have sex with me over the phone. I wasn't desperate about having sex, but I thought that it would be good for our relationship. We turned lights off and imagined we were with each other. I rubbed myself against my bed cover using a condom, and tried not to reach O, but suddenly I felt I was about to cum and even I tried I couldn't stop it.
It sounds weird, but I felt very connected with him, and I didn't experience it as anything close to masturbation or watching pornography. I feel that this doesn't mean I "relapsed", but do you think this could affect my reboot?

(As background, I'm on this journey because of a quite severe PIED. I think hard mode helps best in these cases, but my bf has a very high libido and completely abstaining from O is a bit too harsh for him, I'm mostly no-PM and, since we don't meet so often, largely no-PMO).

Thanks for your advice!