Hi there. Well, let me just say this. We date for a reason. We are supposed to be looking at the other person critically and deciding if the relationship should go long term or not. This man has a different level of sexual libido than you do. Tired and neck pain and stress ---- those things are off and on for life. So, I'd imagine this is him. This is what it would be like long term.
So often, there is a difference between the sexual needs between partners. One wants it a lot more than the other and it is a constant source of strain on the relationship.
Don't go there hon. You two are not compatible sexually. Don't try to put this on you and make it YOUR job to get his libido/sexual appetite back up. That's his responsibility. But it does often happen that things start hot and heavy and peter out. Sounds like this is the case.
If you want a more sexual partner, I think you're going to have to begin dating another guy. good luc
Maybe you should find a partner to meet your sexual needs, as he may just not want sex as often as you he might not be the sexual type of guy. Have you thought that maybe he may of met someone else? sorry to say that but sex drive with a current partner decreases if they are having an affair. By the sounds of it maybe you should confront him or you could wait it out a few more months as maybe this could just be a hicup as he maybe stressed with work or something like that? Good luck