How much sex should a 22yr old have with his/her fiance a month?

We are engaged and love each other we live together .. both of us work a lot and help each other out.

. but we rarely have sex ... .I figured that maybe hes just really tired and or is going thru depression so I stopped pressing the issue ... but I am feeling sad I know my body isnt the best shape (195lbs)but neither is his(250)... and hes said since it is so hot out(90s) he doesn't want to because of the heat and doesnt like the feeling of our sweaty bodies rubbing.... and if the fall or spring when its not so hot he just doesnt really try to have sex then either ....

When we kiss and touch it usually goes like this :

kiss, touching, *attempts sexfor 10 ~15 mins* we stop and I give him a hand job or bj and he sleeps leaving me unsatisfied and sweaty....

Or like this :

He RARELY gets the urge to have sex but I dont feel like going thru that ^ so I just cut to the chase and give him a HJ or BJ :_/

What can I do ? I really love him and tryed to bring this up but I need help