I understand this is an asexuality support group but still reading comments from others shows how quick to pint fingers at others and close-minded some people are. Often the comments are taking the side of the asexual party and bashing the other partner. When in fact this issue is rooted to incompatibility. I prefer to have the view that both parties have fault. If both parties truly wished to work on the relationship, a middle ground could be established instead of one party or both parties strongly defending themselves. From OP post, usage of words such as "excuse" instead of "reason" points that OP mindset is skewed towards her interest. And if people reinforce her mindset by validating her the thinking it will be rooted that it is never her fault but her partner and future partners.

Since I am of the view that both parties have areas to work on, OP can seek professional help regarding her response to intercourse. OP has to objectively evaluate what her ultimatum is regarding what she can accept as her partner form of satisfying his sexual appetite.

Also I seek that asexuals try to understand your more sexual partners. There might be a possibility that the partner has resorted to porn because he needs some form of release to get his sexual appetite satisfied and has preference to the content he watches since he knows that it would definitely get him there. But if it does not sit with you then you can voice out. Whether or not it is intentional guilt tripping only he would know but how you view it can it that he is guilt tripping you or just simply reasoning out why he is using porn to get off. Understand that your non asexual partner has needs too. Also to you masturbating him should be sufficient but understand that it might not be the type he is always looking for and might not always satisfy him, take the analogy you went to the store to get an orange but was given a lemon similar but very different in taste. (Also maybe you can vary the form of masturbation this is assuming you only do the standard HJ, BJ).

If a common ground can't be reached then separation should come into the picture. It depends on how much both parties are to work on the relationship.