You asked

Will my vagina stay stretched out after delivery?

Factors that influence how stretched your vagina becomes due to childbirth, and how much it shrinks, include; the size and weight of your baby, the number of children you have had, the seriousness of vaginal lacerations, or surgical procedures involved during delivery, and whether or not you do Kegel exercises.
Due to relaxation and stretching of the pelvic floor muscles, your postpartum vagina will be larger, and this is more apparent if you had a big baby. Furthermore, the pelvic floor muscles lose more tone, after every successive birth. The only way to “fix” toneless, loose muscles is through exercise. Well-exercised muscles increase in strength and size, the result of this is a tighter vaginal canal. This is where Kegel exercises become vital to rejuvenating your vagina.
Kegels involve perineal tightening. This action strengthens and tones the muscles that surround the openings of the vagina, urethra and anus. Besides helping restore your vagina's tightness, the Kegels are great for treating and preventing incontinence, both anal and urinary. To make sure that you are exercising the correct muscle group, contract the muscles that you use to stop the flow of urine – these are the muscles that are targeted by Kegels. You aren't supposed to do Kegels while urinating, but you can use the flow stop test to confirm that you are doing the exercises correctly.
Start Kegel exercises slowly, so that your muscles gradually build up strength and tone. Doing too many on the first few days will cause muscle fatigue. As you become stronger, you can increase the length of each contraction, as well as the number of contractions you do per day. Do the exercises in sets of ten, and do three or four sets, three times a day. These exercises can easily be done while you are busy with other activities, like watching television, commuting, and talking on the phone.

More questions

There are some very good reasons that you would want to avoid sexual intercourse.
Your vagina will naturally shrink after delivery, as your body heals, but whether it returns to its original size, depends on a number of factors.
Your menstrual cycle usually starts towards the end of your breastfeeding phase, but how regular it is once it is back varies from woman to woman.
It is not uncommon for women to experience pain and discomfort during sex, for the first couple of months after having a baby.
The delaying effect that breastfeeding has on the return of normal menstruation has an effect on fertility and can be considered as a method of contraception – although it is not a very reliable one.
The Intrauterine System, or IUS, is an effective method of birth control that is safe to use while breastfeeding.
It is true that some women experience a drop in their sex drive while breastfeeding, however, this isn’t always the case.
The return to your normal cycle is not a hard and fast rule and it can take anything from a month to a year before your first post baby period happens.
It is entirely up to you and your husband as to when you want to start having sex after the birth of your baby. The best thing to do is to have patience and wait until your body is ready for sex after your baby is born.
As very often happens, if you are just too tired to have sex after a long day, then tell your husband. If he is understanding and clever, he will help you as much as he can. After all, you will both benefit from this.