To directly answer your question; quite possibly.
I know some stoic, pro-cannabis smokers will disagree- more so, because they don't like their habit being seen in a negative light- but yes, smoking dope will kill the sex drive. Especially, long term heavy smoking. Smoking affects blood circulation. Sexually feelings are controlled by excessive blood flow to the genitals, so it's logical that long-term smoking affects sexual feelings. However, that said- some occasional smokers/first time smokers will find it enhances sexual sensation, as nerves become hyper-sensitive to touch, smell & sound (it increases the olfactory senses). After smoking regularly and over a prolonged time; the hyper-sensitivity fades to degree. Hearing & smell can still appear hightened, as can feelings of hot & cold, but skin sensations don't feel as strong as at the beginning of smoking.
Yet...you've also mentioned that she's easily upset & possibly over-reacts to some things (rather than letting them go).
And that she's in her mid 40's. Soooo...I would guess that there is also the valid factor of the menopause.
It sounds as if you might be looking at both the cannabis addiction & the menopause as causes to her behaviour & lack of sex drive. I'm not quite menopausal (yet!), but have been a friend of Mary-Jane for many years & know many 'friends' of hers (past & present). Lack of sex drive appears to be a common thing in long-term, heavy smokers- mostly in men, but it occurs in women too. There's not only the factor of slower blood circulation, but there can be problems with energy levels too. Sex is athletic (usually) & being stoned is correlated with feelings of relaxation; thus, it doesn't necessarily need an expert to work out that being very stoned is going to be detrimental to 'getting-it on'.
However- again, that said- each smoker (especially long-term smokers) is an individual & has individual experiences with their habit. Personally, I smoke & clean or smoke & write. I don't 'mong' & I don't have a dip in energy when stoned, yet when I don't smoke- I get hyper-active. And I can't exclusively say how it's affected my sex drive, as I don't date!
I think you need to speak to your girlfriend & see if she sees the same issues you do in your relationship and if she can attribute a cause. She started smoking at a very young age, so I'm intrigued as to why she started smoking in first place. I would also advise you keep an open-mind as to her reasons towards her lack of libido & emotional sensitivity. She may have issues that are related to her childhood/ teenage years or confidence. Why does she smoke? What does it still do for her after all these years? Are there any other addictions involved (alcohol, gambling, risk-taking, etc)?
Every teenager starts smoking for their own reasons. For some, it's peer pressure, experimentation or simply because 'they wanted to'. But for some, it's to block something out or ease feelings of unstability & anxiety.
I would suggest you talk to her- reasonably & with an ear ready to listen.
Best of luck.
Hello. Yes, we all did some experiments with weed, we did some experiments with marijuana and sex, I did it as well, but I don't think that you can blame weed for your good or bad sex life. I was using marijuana as well, and I can say that sex was amazing, but the only reason was that I was fully relaxed, all my muscles were relaxed as well and I never had fear about anything. So, I did it once, I did it twice, etc. But when I didn't have marijuana, I got scared. I got scared that I will fail and that I will have to fake. Then I realized that this is all in the head, so that is how you need to behave about this. Marijuana maybe can help you have better sex or better sleep, but that is temporary.
so I know this is really late and maybe even now irrelevant, but I would always get high before having sex. high sex is the best sex and i'm sure every smoker would agree. if i wasnt with my fiance after i smoked i always masturbated (maybe too much info) but what im trying to say is high and turned on go hand in hand.