Good questions. For starters, we should clarify the role of asteroids in astrology. They are minor energies and pretty much cast only a one degree orb either side since they are so minor. The only real aspects asteroids can make in synastry charts is through exact orb aspects. I tend to read asteroidal influences as subtle inner capacities that can resonate in weak urgings from time to time but not the sole force behind any major life theme (and sexual compatibility is a major life theme to many souls). While the Eros influence may inflect some of your Libran sensibilities in matters of desire and the Sagittarian Eros is compatible with Libra (as the signs are sextile--no puns intended!!) if they do not fall within the exact degree of sextile aspect then there is really little reason to claim that it will enhance sexual compatibility. Like I said, the asteroids relate to inner impulses and these fluffy yearnings can be shared in a sexual relationship but only implicitly and never in an overt way. Psyche adds to sexual relations through its role as a gate toward the inner mental and emotional relationship one has with another via dreams, desire and longings. Psyche in Aquarius squaring your Psyche in Taurus indicates that there may be some different internal illusions that may demonstrate subtle differences of the ideal ways of relating between both parties. One partner may see the other in a different way in their mental construct of the relationship. In short, those Psyche aspects aren't very compatible (but, again it depends on the exact degree). That said, these issues bear little influence on sexual astrology and serve only as, say (and forgive the candy-coated metaphor) one of many sprinkled candies on the icing, on the cake.
If you want to get to the "cake" part of sexual astrology you must look at the eight house and the ruling planet and see how it compares with your eight house and ruling planet. There are also many possible combinations that make for a sexually compatible synastry chart; for instance, if the partner has their Moon in your 8th house then that resonance will completely outweigh any kind of asteroidal influence--this is an influence that is highly compatible for a loving, emotionally alive sexual relation and exchange. Planets to watch for sexual compatability are Mars, Venus, Moon and Pluto and of course the 8th house....The Sun and the 5th house may play a role as well. I would stick with the 'big guns' for your considerations in this pursuit and deal with asteroids only in a minor way. I hope that this helps you in some way. Let me know if there is something I may have overlooked.