It appears that testosterone has NOS-independent pathways as well. In one study, castrated rats were implanted with testosterone pellets and then divided into a group that received an NOS inhibitor (L-nitro-L-arginine methyl ester [L-NAME]) and a control group that received no enzyme.  The castrated rats that were given testosterone pellets and L-NAME still had partial erections, a result suggesting the presence of a pathway independent of NOS activity.
Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue, however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection can also be a sign of an underlying health condition that needs treatment and a risk factor for heart disease.
Psychological causes include depression, stress and anxiety. Men sometimes worry about getting a new sexual partner pregnant so do make sure you mention contraception. If the relationship is relatively new your partner might be nervous about ‘performing’. If they don’t manage to get an erection, this can add to the tension and pressure the next time and further compound the issue.
Stiffy Solution: Frustratingly enough, the only solution to exhaustion-based impotence is to get some rest, which is obviously difficult (or your dude wouldn't be having this problem in the first place). But if your guy has been resistant to getting help for his insomnia or asking for different hours at work, the inability to get his nine iron out on the putting green might be the thing that finally motivates him to make a life change. So, at least there's that.
The trouble is, most people don't know that sexual dysfunction can be a warning sign of something more serious. Dr Graham Jackson, a cardiologist and the chairman of the Sexual Advice Association, would like to change that. "People aren't aware of the underlying causes of their problems because they feel well otherwise," he says. "They'll say, 'It's my age' or 'I'm nervous because I'm in a new relationship.' But every man with erectile dysfunction should have their heart and blood pressure checked."
Vascular: Anything that affects the flow of blood to the penis can result in erectile dysfunction. The main culprit tends to be atherosclerosis, the condition that narrows arteries and which can result in poor blood circulation, high blood pressure, heart disease and stroke. Atherosclerosis causes about half the cases of erectile dysfunction in men over 50. Also, the veins through which the blood leaves the penis may not be working properly, allowing the blood to leave too soon.
Smoking damages blood vessels, inhibiting blood flow throughout the body ... and I mean throughout the body. While studies have found that men with erectile problems only make up 20 percent of the general population, 40 percent of men with erectile problems are smokers. And a 2011 study of a group of male smokers with erectile problems found that 75 percent of them saw those erectile problems disappear after they quit.
Treatments include psychotherapy, adopting a healthy lifestyle, oral phosphodiesterase type V (PDE5) inhibitors (Viagra, Levitra, Cialis, Stendra, and Staxyn), intraurethral prostaglandin E1 (MUSE), intracavernosal injections (prostaglandin E1 [Caverject, Edex], Bimix and Trimix), vacuum devices, penile prosthesis and vascular surgery, and (in some cases) changes in medications when appropriate.
I know it’s awkward to talk about money like you’re business partners but partners is just what you are: You’re fiancés who share finances. So you need to be very clear about what this merger means. Right now, it doesn’t sound like you’re being very transparent with each other. Why were you surprised to find he was making more and contributing less than you feel he should? Do you not know how much he makes? Does he not know how much you expect him to pay back?
In some cases, ED can be a warning sign of more serious disease. One study suggests ED is a strong predictor of heart attack, stroke, and death from cardiovascular disease. The researchers say all men diagnosed with ED should be evaluated for cardiovascular disease. This does not mean every man with ED will develop heart disease, or that every man with heart disease has ED, but patients should be aware of the link.