V.,
I am a mother who stays home with her 3 kids (with the same close spacing as yours), having put my legal career on the back burner for now. Having said that, I have left infants to go on international trips five different times now, and it has worked out fine. Each time I made sure my kids were with people I really trusted, and that the situation was a win/win for those watching my kids, i.e. I made sure they were paid well and that they had built-in breaks such as an occassional sitter (just like I would need). The other thing you need to understand is that you can literally contact people via email from ANYWHERE in the world now. When my husband and I went to Indonesia this past July, we were in the middle of nowhere as we contacted the couple watching our kids every day for an update, and were reassured as they filled in the details about how the kids were doing. If there was a glitch I was able to provide very specific instructions/guidance that way, which was very helpful.
I cannot express how much it has meant to my marriage to have that time with my husband and to get a sense of adventure admist the monotony of parenting little ones. Allow yourself to experience all the dimensions of yourself. If you have people you trust to watch your little ones, you can do this. It will enrich your life, marriage, and actually make you more complete and interesting to your kids.
Best of luck!