On SAHDs. This was years ago, but one looked at our family calendar and saw "moms' night" penned in on a Friday. I told DH "This is wrong, moms' night is Saturday!" He said "no, your moms' night is on Saturday, mine is on Friday." I had a group of moms I would hang with when I was a SAHM, but when we switched, DH found his own circle of moms for play dates. He was the only SAHD in the group, and it worked. (Actually, my "moms' group" does have another SAHD, and he attends play dates with his kids, and the moms are all welcoming of him. But on moms' night, his wife comes, not him.)
I think pretty infrequently about the income we've given up to have a SAHP. For our 1st kids' year, I was the lucky one, and I gave up my 80K base position to be at home. We lived on my husband's 25K salary. And it was easy, because for about 9 months before that (right after we got married and returned from our honeymoon with a baby on the way!), we lived on his income and essentially saved all of mine. We switched and DH has been a SAHP for about 4 years now. DD1 is 5 and DD2 is 3.
We always wanted to have a SAHP. It was always going to be DH, but I happened to be in a job I wasn't fond of at the time we were pregnant. Because of our frugality and savings, we were confident we could make it a year w/o my income. (BTW, it was 2009, we did not dip into savings at all that year, and our NW went up, and we paid off the 10K of student loans he brought into the marriage, and I rolled some old 401Ks over into my Roth and paid taxes at a nice low tax rate.)
What I do think about more often is the income we'll get when both kids are in school for a full day and DH has time to go out and make some money!
We essentially plan FI around my income alone. Anything he can bring in to boost it is gravy.