Marriages that have a good foundation, rooted in Jesus, last a long time. Those where one spouse has died is not an ended marriage, but a couple that are on two different plateaus. (sort of speak)
Asking him/her to keep you in their heart even unto death isn’t asking a lot of someone who is IN LOVE with you. Their love doesn’t change because you are no longer on this earth. What happens is, it’s still there, but because of WHO GOD IS, if HE so allows, that LOVE can be shared with another.
Is this bad? Heavens no; GOD IS THE MIDDLE THREAD.
Does the new spouse try to fit in the shoes of the deceased spouse? OH no, that isn’t what they were molded to do; God sets the standard and the precedence.
Never let go of what you had with the spouse that has go on; remember what brought you together and the good times you had. Why? If God allows you to marry again, you will share that GOOD PART OF YOU WITH THE NEW HUSBAND/WIFE.