My is too thick for my gf. what can we do to help our life?

I have been with my gf now for over 5 years and we try to have a regular life but its a little difficult because i have a pretty thick . im 6.75" long and 6" thick. We are only able to have once a night. she is never able to have more than once in a day or even back to back days, usually 2 days in between , because she says that she gets really sore and its really unpleasurable to her to do it more than once. i think other factors also go into it such as her liking it pretty hard (not slow and sensual) and i usually take about 25-30 minutes to from (what can i say i like to please her...it doesnt really hurt her all that much while we are having . its pleasurable to her and she usually s but after a while 20 minutes or so she starts to get pretty sore and starts to ask me to try and finish or she'll finish me off orally) What can we do for her not to get so sore or am i just too thick 4 her? BTW she's a petite girl 5'3" 115ish and im 5'5"