The Legit badass person you call yours for the rest of your life that has your back and never gives up on you
Look Shackelnerd your Lifemate has out did himself again
by Hd#48 October 20, 2019
1) Your straight best friend
2) Your partner in crime
3) Your sidekick
"My name is Jay and this is my heterosexual lifemate, Silent Bob"
Jay and Silent Bob
by tandre August 4, 2008
A best friend who is so close, that were they not to match your sexual orientation, you would be married to them. Other sexual orientations may use "homo lifemate" or equivalent.
Yeah Dave's my hetero lifemate. We tell each other everything.
by Dustin Freeman November 29, 2005
your closest friend of the same sex, the person you'd be with if you were both homosexual.
*on the phone*

jack: "i miss you man, when are you coming home?"

phil: "next thursday...only 5 more days!"

jack: "i can't wait to see ya bro, i have so much to tell you...you've really been missin' out!"

phil: "i love you, man!"

jack: "i love you too, bro!"

*off the phone*

tina: "man, if i didn't know any better, i'd think you two were gay together!"

jack: "shut up! he's just my best friend, my bro, leave me alone!"

tina: "don't get so deffensive...i know you two are just hetero-lifemates."
by girl7 December 7, 2006
Your closest platonic friend.
Chris and Johnny B are always together.
But that's cool.
They are heterosexual lifemates.
by IceIceBurghy November 4, 2008