Mars will be exiting Pisces soon, but while he's still in this sign, here's a post about the Tarot card associated with this planet/sign combo.
The 10 of Cups is the card of ultimate happiness and emotional achievement. It represents a situation that meets (or seems to meet) your wildest dreams. Since it's a 10, it's a peak achievement. The wish that manifested with the 9 of Cups (the Wish Card) has ripened. You can't get any higher than the 10 of Cups, so there's also a feeling of peace and contentment. You've arrived, so you can relax now.
When you pull this card, it can mean that your current situation, or what you're aiming for, is golden. It represents anything that feeds your dream of ultimate happiness: family, romance, career, chocolate cake.
But, be aware this card is so good it can be a warning that your expectations are wildly out of proportion to reality. That new relationship may be perfectly fine, but it's not going to be perfect. You'll still get something (and it will be pretty damn good) but it may fall short of your technicolor dream. If this card is reversed, it means the ideal situation is busted. Not only is it not perfect, it's sprung a leak and there are serious problems (involving negative feelings...unfaithfulness, disillusionment, escapism, etc).
Drawing a connection to Mars in Pisces, this emphasizes Pisces as the last sign of the Zodiac: completion. Mars in Pisces represents the efforts you take to achieve the dream. But as often happens with this sign, it's easy to veer off course or shoot for something so beautiful that it doesn't exist. Then again, maybe your actions have taken you exactly where you want to be, and now you can just melt into the moment.
Tarot card pictured is from the Ghosts and Spirit Tarot by Lisa Hunt.