You will still get erections and orgasms while wearing the thermal ring and practising male thermal contraception..
The amount of sperm you ejaculate is about the same but it doesn’t contain as many spermatozoa as it used to (contraceptive threshold: concentration of spermatozoa < 1 million/ml).
Your hormones and manliness remain unaffected.
Your sex drive and ability to have sexual intercourse remain unaffected as well.
The only change is that you cannot conceive a child for a given period of time. If your decision is carefully pondered and you do not feel forced to do it, then you probably won’t regret your choice.