Abstinence & Celibacy Support Group

although its probably not what youre looking for, you might get a better start on this goal, if you check out some catholic groups. otherwise i dont know.

well it's probably bs but there are some theories that support your... "theory"

supposedly, famous football clubs and national teams (like argentina) forbid their players from having sex for 24 hours before a big match

supposedly for bull fighting, they don't let the bull ejaculate...ever in his life

anyway, just saying that there are people out there who believe what you believe. maybe you can find their group!!!

Isn't semen retention more of a Tantric thing?

It can be part of it

Honestly, I think that most any Christian church you join will support your decision. And since we are on the subject of keeping your body pure, you may find that the best way to do that is to give your whole heart to God. It may sound cheesy or old-fashioned, but it's true. God will make you new. The truth is that we cannot be clean without Him.
Please, feel free to let me know what you think. I wont preach at you or try to push God on you. I would just really like to hear your views on the subject. I wont be offended either way and I'll do my best not to offend you. So even if you don't reply, the best of luck to you... and your endeavour is doable :)