While I would never say you should do something out of obligation, I can certainly see why hubby is feeling left out. True he may need to come to terms with his issues, but you are out getting attention from your bf while he is alone, AND he now feels he has no connection with you due to the lack of sex (from his perspective).
Actually, I do understand the logic that he might feel differently if he too had a gf. Reason? Because without having that experience, how does he know for sure you still love him the same? However, did he have a gf, he would have the experience of finding out that doing so did not change his feelings for you - or if it did that he is probably mono.
While there are those who are able to see themselves as individuals and conduct themselves from that perspective, it is rare and it takes practice. Many see themselves in terms of their relationships and in those cases can be very attuned to the concept of equity.