With Hermione, his initial reaction would be to go to her, he does love her and since he got over the hurdle of admitting his feelings and marrying her, he would defiantly start towards her, but he would see she was pregnant, and I believe that would stop him in his tracks. He would probably stammer and point at her belly then look up at her.
What happens if his family is his wife, Hermione? Would he be happy to see her?
Would he jump right into the reason for his disappearance? Would he go right up and kiss her or embrace her?
Now, what happens if he had left on an Auror mission, totally secret and undercover and didn't tell Hermione he was leaving?
What if she was pregnant when he left and he didn't find out until he returned? How would he react to the pregnancy?
From this question, I take it that Ron's assignment was not suppose to last as long as it did. That in fact he was
How would he react to Harry, Ginny, and their new born son when he returned after being missing? Harry, his boss, not even find our gangly looking redhead.