Also, my erections are better some days than others. I'm feeling pretty bad about this. When we have sex, I just don't know what to expect. In the past, I've always been very healthy in this department. While any problem in the area of sex is upsetting to a man, nothing generates as much concern, anxiety, shame, and even terror as the inability to get or maintain erections.
Erection problems can be mainly physical, mainly psychological or both.
If it's a physical problem, you'll need to see a urologist who specializes in sexuality issues. Since you can get erections but sometimes cannot maintain them, it is more likely that your problem is more psychologically based than physical. If the answer to these questions is yes, you probably don't need a urologist. The main difficulty for you may well be how you think your penis should function. A great many men just assume that their penis should be erect and ready at all times, and are disappointed and upset when they realize it's not.