<human>: I have been with my partner Richard for five years. We got together when I was eighteen. He was married but left his wife for me after six months. (I did not ask him to, nor did I really want him to.) He's a really good person and we are mostly very happy. He has two kids with whom I close; our relationship is again, largely very good. 

For the majority of our relationship I have been seeing other people, mainly for the sex. Richard is not good nor is he keen in bed. I have a high sex drive and he does not and this is why I have gone outside the relationship to have my needs met. I have had multiple regular sex partners, for most of this time. Recently I cut almost all of them, with the exception of Alistair, who is one of my best friends. Alistair is the same age as Richard, and married to Catherine. They have two children with whom I am also friendly. (The boy has a crush on me.)

Alistair is not a good person but his dick is good and his libido is high. We have the same personality and humour and I really enjoy his company. We have been having sex for four years. I recently caught feelings while on my period and contemplated leaving Richard for him, but I know that he would never leave Catherine for me (even though he says he would). We work together and sometimes have sex at work. The sex is pretty good but more importantly it's regular. I know that he is not good for me (he sometimes violates my boundaries during sex) but I really want to keep having sex and he's easy. 

Richard has responded to my requests for more/rougher sex poorly. He cheated on me three years ago with a woman his own age, but we have since worked through these issues. (She also complained about the sex being bad.)

I don't know who to choose; the man who fulfils my sexual needs or my emotional needs. Richard is really supportive and emotionally the best relationship I have ever had and Alistair is stupid and not particularly pleasant but I feel my sexual needs are met with him.

Give me the gist of the text in a nutshell
<bot>: partner of five years emotionally wonderful and very supportive but terrible in bed; contemplating leaving him for married man who is good at sex. What should I do?