This sounds like a good time for communication. He needs to maybe be honest . . . he's older. And for some men, getting older can mean it is harder to get erections and it takes a lot of visual stimulus and direct contact. IE: porn and masturbation. And you can tell him how your lack of intimacy is making you feel. Ask him what is going on. Tell him what is going on with you. Sometimes too, masturbating for some men (maybe women too) is just easier. There's no build up or expected cuddling afterwards. This doesn't make it acceptable to ignore your needs or to not be intimate with his partner, but understanding why it may be happening is important so that you don't assume he isn't attracted to you. By the way, do you have any other issues in the marriage? Lack of sex can be a sign of other marital problems. We're here to help! Come back and update us!!
It's too bad that he may have been spooked out of the possibility of your introducing porn into your marital bed (since you became aware he used it and it sounds you wouldn't mind it being part of your sex life if it helped him). I can imagine that you're pretty perturbed and sad :( I'm so sorry this is hurting your feelings. The reality is that he has a responsibility to his young wife and he owes it to you to work on this issue that he's creating and you're suffering through. As Annie Brooke suggest, i think therapy would help, but i wouldn't give him the opportunity to be spooked again into making another automatic NO to therapy by asking him. Instead i suggest that you go to a marriage counselor yourself. Open up to them, and ask them how you might be able to help. If you find a really helpful therapist that would do their best not be make him feel awkward, (someone you feel he might respond to talking to about something so personal) and then (with coaching from the therapist) draw him into talking about the possibility of making your marriage better.
In the interim, continue to enjoy your relationship and building trust.
Knowing your ages might help us to help you.
Have you considered the possibility that this relationship has issues that are irreconcilable? Sexual Incompatibility is a reason for divorce for certain. Perhaps a partner that is you own age and more sexually compatible might be a better fit for you for a lifetime. Perhaps a partner more fit would draw you into hiking ,camping etc. Speed boating. There are many other areas that might be affected by his age and not being as robust as yourself. It wouldn't mean that you wouldn't always love and care for him, but he may also be happier with a partner without the expectation of physical love.
Your in my thoughts and prayers, and if ever you need a shoulder , please feel free to private message me friend.
You have mentioned the age difference more than once: how many years apart are you and what are your ages? If you were 25 and him 68, for example, I might see that he would find masturbating less of a challenge than having sex with an active, young wife who has expectations. (I don't mean you sound pushy or domineering, but just that you sound as interactive as you might be with someone in your own age cohort, and that might be more than a male who is a lot older expects of women.) If he comes from an era where the man is the leader and initiator in bed and the woman is supposed to be the passive recipient, he might be concerned that he is not satisfying you, especially when you give him heartfelt pleas that you (basically) aren't satisfied. Do you think he would go to couples counseling with you, so he could hear what you are saying as something besides a criticism?