Many women would prefer the water based products since the oil based ones are harder to remove, can stain sheets, should not be used with condom use (they can increase breakage) and may leave an odor afterwards.
In addition, some women are allergic to some of the vegetable oils such as olive oil (and my partner is allergic to coconut, including coconut oil).
It's probably fun to experiment with several on the market.
If this has happened after a bowel movement (and you are certain this is rectal and not vaginal bleeding) then perhaps you have a bleeding hemorrhoid; hemorrhoids are not all that unusual during pregnancy.
You cannot tell if your partner is cheating based on whether her vagina appears looser or more swollen to you. Keep in mind that she is pregnant and there can be hormonal changes that take place during this time.
Honestly; my background is working with male veterans, many of whom are far older than you and a fair number with a far longer history of substance abuse than what you've gone through.
Do some have issues with erectile dysfunction (as opposed to low libido; two very different medical issues)? Yes. Those tend to have the classic diseases associated with ED; i.e., neuropathies with diabetes, hypertension, and heart disease.
What you are asking (I'm assuming) regarding hormones involves whether the "spirit is willing" as opposed to a "the spirit is certainly willing but the flesh ain't responding" type of question. Even our 90 year old veterans with a good 50 to 60 years of fairly heavy substance use under their belts often have a more than willing spirit regarding these matters as many of our nurses will attest to.
Your problem, at a young age of 24 is that if you worry excessively that you have permanently damaged yourself over this short term substance abuse history that, psychologically you may will yourself into doing exactly that.
The human body has an amazing ability to heal itself, especially for such a young person as yourself...and without the use of a special diet, exercise, herbs, potions, vitamins, minerals, whatever.