"Cause" in English can be translated to "原因". If you're looking for multiple couple avatar ideas with an English name that relates to "cause" or reasons, here are some creative suggestions:

1. WhyNotUs

• Meaning: A playful take on the word "why" (a common cause-related question) combined with a romantic sentiment.

2. ReasonsToLove

• Meaning: Focuses on the many reasons two people love each other.

3. CauseAndEffect

• Meaning: Represents how one person's actions lead to the other’s feelings, symbolizing their relationship dynamics.

4. OurStoryBegins

• Meaning: Every story has a starting point or cause; this reflects the beginning of their journey together.

5. FateBroughtUs

• Meaning: Suggests destiny as the reason they met and fell in love.

6. HeartOfItAll

• Meaning: The heart being the central cause or reason behind their connection.

7. TwoHalvesOneCause

• Meaning: Indicates that both partners share a common goal or purpose in life.

8. LoveIsTheAnswer

• Meaning: Love is the ultimate cause or solution to everything.

9. MadeForEachOther

• Meaning: Emphasizes compatibility as the main reason for their bond.

10. SoulmatesByDesign

- Meaning: Implies that fate designed them to meet and fall in love.

If you'd like specific designs for these names as couple avatars, consider incorporating symbols like hearts, infinity signs, puzzle pieces, or intertwined initials to visually represent unity and shared causes!