Overall there is merit in the statements but not because of the signs - more because of the nature of the planets and their relationship.
Venus is the lesser Benefic, Mars is the lesser Malefic - Venus is usually (though by no means always) a force for good, Mars is the opposite. A Mars/Venus conjunction is never a good thing. The overall balance between the two will depend on their sign placment, and thus will vary throughout the zodiac.
Aa Mars/Venus conjunction in Scorpio would see Mars as the dominant of the two (the reverse would be the case of a conjunction in Libra) The reason being that Mars and Venus rule opposite signs, so if the are in conjunction in a sign that one rules, the other is in detriment (though other factors might balance this). In the current applying conjunction, Venus is slowing down and is actually slower than Mars, but this is balanced by both being occidental (visible in the Western sky after sunset), which is good for Venus but not for Mars.
Now it is planets, not signs that are important - modern sign meanings are the product of the late nineteenth/early twentieth century Astrologer, Alan Leo and are in effect an attempt to implant the characteristics of the planets onto the signs. So Scorpio isn't by any stretch of traditional Astrology an 'intense' sign (though it's not seen as a desirable placement by any stretch of the imagination - it's associated with cess pools and other nasties)
Venus does have a role in traditional relationships - it is a general significator for women and might well be used in relationship horaries, or in natal Astrology where we are specifically looking at marriage prospects. It might well be used in Primary Directions for predicting the time of marriage. If the ruler of the seventh House (Lord 7) is in sextile, trine or conjunction with Venus, this would also be favourable to relationships - just as squares or oppositions from Mars would be disruptive to relationships.
So to summarise:
Venus/Mars conjunctions are almost never good for relationships, except in the situation of them being the significators in a relationship horary.
A conjunction in Scorpio has Mars as the more dominant - and it is Mars that supplies any urgency, or need to be 'forward'.
Jealousy and Possessiveness are signs of weakness, and Mars is not weak in Scorpio, so that might be something more associated with Mars in Libra - Or a debilitated Venus, especially one conjunct Mars.