Need some advice co-worker has started to come onto me and my wife and i lost our son 2months ago....?

My wife and i lost our 2 year old son a couple of months ago and we are both still taking it horribly. Well to be honest our marriage has never been so low our two year old was our first and my wife is 6 months pregnant with another baby boy and were both extremely wary about to and scared. Our Family and friends have been amazing through this super hard time and i feel so vulnerable and at the same time i need my wife so much right now but we are both so distant with one another and that's really hard. We have both been going to counseling to try and help it its working i think unsure. Well a younger co-worker who is 24 (my wife and i are both 27) has been coming onto me lately and today she told me she is inlove with me =/. Well for some reason it has started to make me feel more loved then my wife is loving me and such. But at the same time i get the feeling she is trying to take advantage of me and not sure what to do. I talked to my wife's sister who her and i are very close grew up together today and she was like you better not and all of this other stuff and that this girl is just toying with my feelings and taking advantage of me while i am vulnerable. Not sure what to do,Advice?