Both are important; and both are subject to deep disrespect in far too many relationships.
Just consider the negative connotation from the expression "having a past"; it's particularly nasty when applied to women, unfortunately.
And for problems with heritage, when was the last time you heard an in-law joke? Not long ago, I'll bet.
Disrespect for either your mate's personal history or their heritage is a not-so-subtle way to disrespect the person. It's also a way to maintain an unhealthy form of control in the relationship.
When you marry, you don't build a life with a person new-spring from the palm of God's hand; you marry a complex web of past relationships, experiences, family, and genealogy. The wedding limousine can get crowded; not to mention the marriage bed.
Let's deal with your spouse's past, first. The approach to showing respect is pretty simple: never bring up anything negative from their past, and never, ever reference current behavior to what you know of their past.
It can take discipline, but it's absolutely necessary. When you bring up "those friends you used to hang out with", you're locking your mate into a past that they can't escape. They may have tried; they may have gone a long way from the irresponsible of younger days.
And when you bring it up, you're negating all the work they did, and saying "you really haven't changed at all".
Based on the past - you've appointed yourself judge and jury, with no hope of appeal.
What you know of your spouse's past, that you don't like...you've got to let it go. That's the beginning and the end of respect.
Respect for heritage is a bit different, because you have to key your respectful attitude to your spouse's view of their family history.
It can be a tightrope walk. Remember the old saying - me against my brother; my brother and I against our cousin; my brother, my cousin and I against the world.
There may be little love lost in your mate's family, but blood can be quite thick, and you're not "of the blood".
That means that your mate may feel fine being extremely critical of "the family"; but you try it and you'll find yourself pilloried, and wondering what hit you.
By the same token, if you defend the "black sheep" of your spouse's family, you can wind up soundly disliked by everyone - including the black sheep.
The best way to show respect is to be agreeable..and never take any side expect that of your mate, and then only in a supporting role. Never take the initiative in either praise or censure of your mate's family, and make sure that your emotions remain as unengaged as possible.
Respect for your mate's past and heritage can be a challenge, the biggest challenge of all, because it fundamentally requires you to...
...keep your mouth shut, and your opinions to yourself.
(Please don't forget to visit my other blog, www.dailygracequote.wordpress.com, for a quotation and a short commentary of grace in marriage.)
This post is linked to Wedded Wednesday, a compendium of really cool posts on marriage. If you click on the logo below, you'll be taken to www.messymarriage.com, which is the springboard to a wealth of information. It's run by Beth Steffaniak, who has a heart for marriage and a soul for God!