Can I just say you sound like a wonderful guy? I know the bar is often kinda low for men, and how you feel about your relationship should be the norm ("more to a relationship than suckin' and fuckin', that's hilarious but a great take if you're comfortable with it, which you clearly are) but it isn't very common.

Your partner should be very happy to have you, and it's pretty silly that she's upset about this. Especially considering you don't throw it in her face when you play and keep it private. There's nothing wrong with being ace, and there's also nothing wrong about enjoying cute girls in bikinis, or eroges. If she's truly sex-repulsed then I would suggest she gets therapy. Not having a natural libido is different than being sex repulsed, which is seems like she is.

Not to say her sexuality is a result of being sex repulsed or vis versa, I believe the two aren't necessarily connected, but being this grossed out by nudity/porn that you don't even indulge in personally is unhealthy. Especially when it's as harmless as game mods or eroge (rather than live action porn that may or may not rely on taking advantage of people; that would be more underandable).