You say you passed the menopause mark (a year without menstruating) four years ago. You use a vaginal moisturizer every three days, and are successful with dilator use. Still, you have difficulty with “full and comfortable” intercourse with your husband.
I suggest that you take the largest dilator you’ve used in to your health care provider. Explain the situation, and have your provider insert the dilator and do a careful exam to see why there’s a discrepancy between success with the dilator but not with intercourse.
The term “hitting a wall” is most often used with the diagnosis of vaginismus. Vaginismus is involuntary spasm (tightness or tautness) of the pelvic floor muscles. Because this is involuntary, you can’t “just relax” the muscles.
This is a clinical diagnosis that can often be treated with dilators, but may also need pelvic floor physical therapy treatment as well. Your provider will be able to help in that determination and then to direct to you a physical therapist with pelvic floor expertise.
Good luck! It’s worth pursuing to regain that intimacy!