Key words ... loving and supportive relationship. It sounds like you've no need to be shy.
The best way to get over your fear is of course do that which you fear.
Channel your inner SexGoddess.

If he's already on the sofa after work, have him sit up but lean back and then get on the floor between his legs. Look him in the eyes and start brushing your hand against his crotch through his (whatever he's wearing). If he's clothed, unzip slooooooowly all the while looking him straight on with a little smirk on your lips. Seductively tell him you've missed him. Take out his p*nis, have a wee little bit of oil handy to lube up your hands and then give that man a nice, erotic hj/bj combo. I sometimes wear silk gloves too for a different sensation or use a toy on the 'boys'.
He may appreciate that you've taken charge and not put any pressure on him to perform if he's tired.
Then again, I'm not a guy so who knows if this will work.