Carbon monoxide can also leak from your boiler system and that is doubly dangerous.
They are open to marriage but prefer to remain single.
Whoever wishes to form a quality relationship with this man needs to understand that the sign of Sagittarius is a continuance of Scorpio while preceding Capricorn, so there can really be nothing superficial about it.
This is why he will rarely choose to do so, even when he is unfaithful or falls in love with someone else.