Very frustrated

Mine and my husband’s sex life has SUCKED lately and I don’t know how to fix it. The sex is great when we actually have it, but there’s always a two week gap or longer between each time. It’s really frustrating because I know my husband loves me and wants sex with me but he doesn’t always put forth the effort to make it happen. He will flirt with me and grab my boobs and down there but it hardly ever carries over to the bedroom. We have been busy lately, my husband has been sick and really tired on and off, and our son (2.5) hasn’t been sleeping well the past week, but the sex issue has been going on for 3 years or so. I feel really selfish even wanting sex but it’s more of an emotional need than a physical need. I’ve cried about it and talked to my husband about it but nothing has worked. When I say something like “I really wanted you last night” he will say “I know…” then the conversation ends. I’m so sick of hoping to have sex only to be let down again.