What is the official position of Christian denominations today about Wasting seed?

Human sperm are known to live for up to 74 days inside a man's body , after which they are reabsorbed by the body. This means that, if a man releases sperm in an ejaculation, the sperm would have been reabsorbed anyway unless that man found a woman within 75 days. There is the story of Onan, but it seems to refer to coitus interruptus (practicing some form of contraception) when a woman is available and the man's holy duty (Levirate Marriage) was to raise children with his dead brother's widow, who would inherit the property. A separate category is spilling seed when one is not dating anyone. Please state what Christian denomination you are answering from (Catholic, Orthodox, Lutheran, etc.) and then explain (with sources) what is the current position of your Church on the matter of "wasting seed", in the following scenarios: 1) Masturbation, where someone is "single" or a wedding is not planned within 75 days 2) Using condoms during premarital sex, e.g. to prevent catching an STD (I understand this one is a bit of a tough one, since premarital sex itself may be prohibited by some denominations, but given that it does take place, there must be some opinions regarding whether health concerns or wasting seed takes precedence?) 3) Using condoms within a marriage (e.g. as a form of contraception) NOTE: This question is NOT asking about abortion or birth control pills.