At four months your baby isn't at the kind of risks of infection that newborn babies are, but breast is always best. My friends little one was breast fed for the first 5 months of his life, and she went to give him formula, but he refuses to take it. He won't drink from a bottle at all, your son may be the same.

Ultimately you must think of your wife. If she is finding difficulties in breastfeeding, you need to be understanding and not heap pressure on her, or else she will be stressed and feel as if she has to breastfeed, rather than doing what she wants. At least she is looking at com-feeding him, and not cutting out the breast milk altogether. And look on the bright side – you can feed him too and have that bonding experience that you haven't felt yet.
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Breastfeeding is the best source of nutrients for a baby. However having a happy and healthy mother is essential for a baby's health and wellbeing. Breastfeeding can be very difficult and your baby will have benefited greatly from the four months of breastmilk he has already had.
Does your wife feel that she can't have a break from the house and/or baby while she is breastfeeding? Talk with her calmly and try to understand why she wants to introduce some formula to your son's diet. She may be feeling isolated, unsupported, in pain, trapped or many other things. If you can find out what is behind her plans, you may be able to assist her to continue at least partial breastfeeding.
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I would first try and tackle the BF issues, there are plenty of lactation consultants who can help. Most people find that once they start with a wee bit of formula, it is a "slippery slope" and not long before the baby is totally weaned onto formula. Good luck.
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i started formula at 6 weeks.couldnt handle breast feeding and my 3 month old is so healthy.
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What is it she's having trouble with? If it's a question of feeling like she's nursing ALL the time, that'll pass as he gets more efficient at draining a breast. Also he can start some solids at 6 months, which won't cut out breastfeeding, but can replace some of it. At 6 months I started giving my daughter some rice cereal with pumped milk in it.
If she's tired from night feedings, consider cosleeping so she can nurse lying down and get some sleep. That saved me!!
Perhaps she could be persuaded to pump sometimes and let you take some feedings. Breastmilk is far and away the BEST food ever, so point that out. Also, germs transferred to your baby enter the breast and come back out to him as antibodies, so it's so good for their health.
Good for you for realizing formula isn't good enough! Be sensitive though, because I'm sure she's exhausted and liable to be crabby!
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http://www.askdrsears.com/html/7/T071000.asp
Mom of a still nursing toddler

You already know that breast milk is best for the baby; but if your wife is struggling it can be stressful for her. That is a personal decision and you both have to come to terms with feeling good about what you are doing. The first year flies by so quickly, your memories should be happy and not worrisome. Whatever decision that you make with the baby's best interests in mind is a good decision, and hopefully you can do whatever will give you a happy baby and happy mom as well.
good luck with this and enjoy your son!
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