I don't do a white sauce - we use marinara, and I don't care for ricotta cheese. If you like ricotta, though, you can substitute it for one of the mozzarella layers:
For the sauce:
saute garlic in olive oil (don't waste money on extra virgin if you are just using it for sauteing - it won't HURT to use EVOO, but if you saute with olive oil a lot, as we do, you might as well have a bottle of the cheap stuff); don't brown it, you just want it soft.
Add 1 12oz can of tomato paste and 1 16 oz can of tomato sauce, reduce heat to low.
Add, ALL AT ONCE (the tomato-based sauce will amplify the flavor of the last thing you add) oregano, basil, rosemary, thyme, and mustard powder; and a little red pepper for kick, if you want. The amount is up to you, but generally, the proportion I use is two of each green, for every 1 of non-green. So, a half tsp each of oregano, basil, rosemary, and thyme and a quarter tsp each of mustard and red pepper. Or half/whole or whatever.
(If using the same recipe to pour over spaghetti, at this point add 1 cup of liquid - chicken broth and vegetable broth work equally well, or you can use water in a pinch. I don't do this for lasagna, though - makes the noodles soggy.)
Simmer the sauce on low heat for a few minutes - baking the lasagna will blend the flavors, so you really don't have to simmer it for longer. If you are adding water and doing it as a stand-alone sauce, though, simmer for about 25 minutes.
Mix into the sauce the already browned and drained ground meat of your choice. I prefer ground beef, but I have a friend who uses sausage. My mom has used turkey, and I've heard of using a lamb/beef mixture. Personal preference.
Assembly:
Boil the noodles as per package directions. I recommend adding a little oil to the water, just to make them easier to separate. How many noodles depends on how many layers, and the size of your pan.
You don't necessarily have to spray the pan - your bottom layer is noodles, and they won't stick. If you want to spray the sides, though, I don't think it'll hurt anything.
We layer noodle/sauce meat mix/cheese, noodle/sauce meat mix/cheese
Typically, the cheese we use is a blend of mozzarella and a hard cheeses, but you can certainly replace one (or all, I suppose) of the cheese layers with ricotta. I personally don't care for the texture, myself. (I have heard you can use cottage cheese instead of ricotta, but I've never tried it.)
Assemble, and stick in the fridge until you are ready to bake it. You really only have to bake it long enough for the cheese to melt, and the insides to get warm. I often make one in the morning, and pop it in the oven when DH calls to say he's on the way home in the evening.
I hope I've at least given you some good ideas.
Enjoy, and a happy birthday for your boyfriend!