Have you tried rethinking sex completely. I don't like the term foreplay. It implies sex is all about PIV. It isn't. PIV is one kind of sex only.
If your relationship is generally very well balanced, in the sense that you're not doing all the nurturing, supporting and making things happen, there's quite a lot you could do to change this. If it's unbalanced, however, you could end up feeling worse if it results in you making all the effort with very little in return.
Initiate long, very passionate kisses and then walk away without allowing them to progress any more. Try straddling him (fully clothed) during an ad break when you're watching TV, kiss him madly, then get off and carry on watching TV as if nothing has happened. The point is not to let it lead to sex.
A BJ resulting in orgasm is sex. As is cunnilingus. Sex should be a mutual thing, but that doesn't mean you have to do both at the same time.
Pamper yourself as if you had a new boyfriend (the spa day sounds great - do more of them). Dress nicely, wear good underwear. Do it for yourself. Don't refer to it in front of your DH asking for validation, just do it because it feels nice. Desire comes from within. Other people turn you on, but they have to be able to stoke a fire that's already laid inside you. When you feel desirable, it is noticeable and sends out signals of attraction.
This is a lesson that maybe your DH needs to get on board with for himself, too. If he's stopped seeing himself as a sexual creature because he's too knackered/got in a rut, he needs to break out of it. Both of you should be finding time to have good old0-fashioned fun, ideally both separately and together.
Hope you manage to improve things.