What I have to offer for existing relationships, is astrological counseling. If you are having problems in the relationship, I can show you astrologically where those area are and how to understand and make improvements. Hopefully turning the problem into a mere issues that is easier to deal with and/or overcome.
For example. Mercury is communication… If one of you has Mercury in Virgo and the other has Mercury in Aries, Mercury in Aries might feel the one with Mercury in Virgo is “holding them hostage” or dominating them because Mercury in Virgo communicates in detail. Mercury in Aries is direct and to the point, Mercury in Virgo cannot get to the point without providing all the necessary details. Mercury in Aries can come off as brash and down right cruel to Mercury in Virgo because Mercury in Aries thinks they are being direct and to the point, but they are not giving Mercury in Virgo enough detail for them to understand properly. This is a hard combination to get past! Believe me, I know this one from experience. However; My grandmother has Mercury in Leo and my grandfather has Mercury in Capricorn and they found a way, so you can too.
Other positions may not be so difficult; but understanding astrology and why your partner or yourself for that matter are doing the things that may be annoying or obtrusive, this might make it easier to deal with one another. It all boils down to free will; what can you handle, what are you willing to change for your partner and what are you willing to accept.
Sex is another big one: Mars… and Eros. If you need sex and your partner doesn’t, this is an issue. Astrologically, you can see why your partner needs it so much and you wont feel like they are just being selfish all the time because they say they need it more and you don’t understand because you do not. If you can see that your partner needs physical intimacy more or even less then you do in their astrology, it will help you to have more empathy for them.