Personally, I could never put up with the "let him cry it out" idea. I had the luxury of being able to wait until my babies were willing to start weaning (I suppose you could say when they "initiated" it).
I thought the responses from Meredith C and from Andrea S were fantastic.
Though you feel that you can't wait, consider having a practice night leaving your son (or son and daughter) with those who are going to care for them while you and your husband are on vacation at the end of June. Maybe a Friday night. You don't mention if your mother will care for them. You may find that, without you around, he may drink from a bottle just fine (like at daycare) a few times during the night. Because it is with someone who is not MOM, your son will most assuredly behave quite differently. Then, when the end of June arrives, three nights (I'm guessing here) without you might be manageable.
Upon your return, I can practically assure you that he will cling to you like a magnet to a paper clip!! Please give him as much attention as he wants until he feels safe that your aren't going to "leave him" again.
One tip I have is to substitute a nighttime nursing session with a snuggle session. Maybe one time a night for 6-7 days before trying for two times each night, etc. Babies nursing at this age get almost all of their nourishment during the day. It is the comforting and closeness (attachment) that is important. Nursing your baby has become time for "Mom and me" time -- which IS extremely important. There are studies which show that loss of this bonding time can slow the baby's stages into independence.
Also remember, your son won't be 17 months old again, ever! All of us parents have to balance raising our children, fanning our marriage life, and making the time for taking care of our selves. You are not alone! I'm praying for you.
Good luck! and I hope your husband starts looking forward to this vacation almost as much as you are!